Trends in survival of patients diagnosed with cancer of the digestive organs in the Nordic countries 1964–2003 followed up to the end of 2006

Abstract

Cancers of the digestive organs (including the oesophagus, stomach, small intestine, colon, rectum and anus, liver, gallbladder, and pancreas) constitute one-fifth of all cancer cases in the Nordic countries and is a group of diseases with diverse time trends and varying consequences for public health. In this study we examine trends in relative survival in relation to the corresponding incidence and mortality rates in the Nordic countries during the period 1964–2003. Material and methods. Data were retrieved from the NORDCAN database for the period 1964 to 2003, grouped into eight 5-year periods of diagnosis. The patients were followed up until the end of 2006. Analysis comprised trends in 5-year relative survival, excess mortality and age-specific relative survival. Results. Survival following cancers of the colon and rectum has increased continuously over the observed period, yet Danish patients fall behind those in the other Nordic countries. The largest inter-country variation is seen for the rare cancers in the small intestine. There has been little increase in prognosis for patients diagnosed with cancers of the liver, gallbladder or pancreas; 5-year survival is generally below 15%. Survival also remains consistently low for patients with oesophageal cancer, while minor increases in survival are seen among stomach cancer patients in all countries except Denmark. The concomitant incidence and mortality rates of stomach cancer have steadily decreased in each Nordic country at least since 1964. Conclusion. While the site-specific variations in mortality and survival largely reflect the extent of changing and improving diagnostic and clinical practices, the incidence trends highlight the importance of risk factor modification. Alongside the ongoing clinical advances, effective primary prevention measures, including the control of alcohol and tobacco consumption as well as changing dietary pattern, will reduce the incidence and mortality burden of digestive cancers in the Nordic countries.

Cancers of the digestive organs (including the oesophagus, stomach, small intestine, colon, rectum, liver, gallbladder, and pancreas) are a group of heterogeneous diseases with diverse time trends and varying consequences on public health. Together, they constitute approximately 20% of all cancers in the Nordic countries. Colon cancer is the most common, with more than 9 000 cases per year in 1999–2003 in the Nordic countries, corresponding to approximately 7% of all cancers in men and 8% in women. Cancer of the rectum ranks second and constitutes 4–5% of all cases. The other sites represent from 0.5 to 3% of the total cancer burden in the Nordic populations [1].

Environmental and lifestyle factors predominate the aetiology of cancer of the digestive organs. Smoking is an established risk factor for cancers of the oesophagus, stomach, small intestine, liver, and pancreas [2–4], while alcohol consumption is associated with cancers of oesophagus, colon, and liver [5,6]. For certain cancer sites, such as oesophagus and stomach, there are also indications of a multiplicative effect from smoking and alcohol on the cancer risk. The other main risk factor for liver cancer is infection with hepatitis B and/or C, rare conditions among the populations of the Nordic countries [7]. Dietary factors have been shown to influence the risk of developing colorectal and stomach cancer, and the best established risk factor for the latter is infection with Helicobacter pylori [8–10]. Low physical activity/overweight increases the risk of oesophageal, colorectal and gallbladder cancer [11]. Other bowel diseases, such as Crohn's disease and colitis ulcerosa, have been shown to increase the risk of cancer of the small intestines and colon [12]. Cholelithiasis is associated with gallbladder cancer and the association is correlated with stone size. Reproductive factors have also been linked to occurrence of gallbladder cancer as the disease is more common in women [13].

A recent study by the EUROCARE group showed that survival from cancer in the digestive tract is highly variable in relation to the anatomical site [14]. The mean European age- and area-adjusted 5-year relative survival estimates in this group of tumours were most favourable for colorectal cancer (54%). Corresponding survival figures for cancer of small intestines and stomach cancer were 42% and 25%, while survival was below 15% for oesophagus, liver, and gallbladder/biliary tract cancer. The 5-year relative survival among pancreatic cancer patients in Europe was only 6% and has been stable for a number of decades. [14]

Previous Nordic studies showed that the age-standardised 5-year relative survival of oesophageal cancer patients was up to 10% (period 1958–1987) [15] and below 20% among stomach cancer patients (period 1978–1992) [16]. International and Nordic comparisons [14,17] have reported that colorectal cancer survival in Denmark fell behind the other Nordic countries and several other European populations, this despite some observed increases in survival with time. Disparities between the Nordic countries in the magnitude of relative survival ratios and the changing trends have been noted in several reports [15,16].

The purpose of this study is to compare the development of cancer survival in the five Nordic countries, Denmark, Finland, Iceland, Norway, and Sweden in the years 1964–2003 following cancer of the digestive organs, evaluated in light of the corresponding trends in incidence and mortality.

Material and methods

The data sources and methods are described in detail elsewhere [18]. In brief, the study is based on the NORDCAN database, hosting comparable data on cancer incidence and mortality in the Nordic countries delivered from the national cancer registries, with follow-up for death or emigration for each cancer patient through to the end of 2006. This study examines cancers of the oesophagus (ICD-10 C15), stomach (ICD-10 C16), small intestine (ICD-10 C17), colon (ICD-10 C18), rectum and anus (ICD-10 C19-21), liver (ICD-10 C22), gallbladder etc. (ICD-10 C23-24) and pancreas (ICD-10 C25). We calculated sex-specific 5-year relative survival for each of the diagnostic groups in NORDCAN for eight 5-year periods from 1964–1968 to 1999–2003. For the last 5-year period hybrid analysis methods were used. Country specific population mortality rates were used for calculating the expected survival. Age-standardisation used the ICSS standard cancer patient populations [19]. Age-standardised incidence, mortality, and 5-year relative survival are presented, as are excess mortality rates for the follow-up periods <1 month, 1–3 months and 2–5 years following diagnosis as well as age-specific 5-year relative survival by country, sex and 5-year period.

Results

Oesophageal cancer

Incidence and mortality. The incidence of oesophageal cancer is higher in men than in women (Figure 1). Finland had the highest incidence at the beginning of the period, but a notable decline was observed thereafter, in both sexes. The incidence in the most recent period was twice as high in Denmark compared to Finland, Norway, and Sweden, incidence in Danish males doubled since 1980, with more modest increases observed in the remaining countries. Among women, incidence increased in Denmark, but remained stable in Sweden and Norway and declined in Iceland. The trends for mortality closely followed those of incidence (Figure 1).

Figure 1. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for oesophageal cancer by sex and country. Nordic cancer survival study 1964–2003.

Survival. The age-standardised 5-year relative survival was at a low level throughout the observed period although it increased somewhat in more recent periods, particularly for Swedish men where it reached 11% in 1999–2003, and for Finnish and Swedish women, with ratios estimated at 20% and 14% respectively (Figure 1 and Table I). The relative survival in Denmark has remained low at 6% in men and 7% in women diagnosed in 1999–2003. The age-specific 5-year relative survival ratios are presented in Table II; the general pattern that emerges is that survival declined with increasing age. Denmark tended to have the highest excess death rates over time 0–3 months after diagnosis, reached similar levels as the other countries during the 1990s among men, but remained at a high level among women (Figure 2). Danish patients still had the highest rate of excess deaths in 1999–2003, 2–5 years after diagnosis.

Figure 2. Trends in age-standardised (ICSS) excess death rates per 100 person years for oesophageal cancer by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003.

Table I. Trends in survival for oesophageal cancer by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1968	403	6 (4–9)	588	5 (3–7)	28	0 (·-·)	369	4 (2–8)	826	5 (3–7)
1969–1973	473	3 (1–5)	527	5 (3–8)	22	0 (·-·)	377	2 (1–4)	955	7 (4–10)
1974–1978	500	1 (1–4)	458	5 (3–8)	25	14 (6–35)	439	4 (2–6)	943	5 (4–7)
1979–1983	554	6 (4–10)	489	7 (5–11)	32	14 (6–35)	430	3 (2–6)	1 050	5 (4–7)
1984–1988	750	2 (1–4)	496	7 (5–11)	28	18 (10–34)	443	4 (2–6)	1 114	6 (4–8)
1989–1993	959	4 (3–5)	544	6 (4–8)	47	18 (10–34)	518	4 (3–7)	1 113	8 (6–10)
1994–1998	1 177	4 (3–6)	600	7 (5–10)	59	12 (7–21)	544	8(5–11)	1 183	11 (9–14)
1999–2003	1 352	6 (5–7)	704	9 (7–11)	46	12 (7–21)	605	8 (6–11)	1 355	11 (10–13)
Women
1964–1968	246	6 (3–10)	704	5 (4–8)	28	8 (2–34)	149	6 (3–14)	457	9 (6–14)
1969–1973	246	10 (6–16)	628	8 (6–11)	15	8 (2–34)	141	3 (1–8)	437	10 (7–15)
1974–1978	286	5 (3–10)	582	8 (6–12)	18	9 (3–27)	167	7 (4–12)	400	6 (4–10)
1979–1983	303	7 (4–11)	593	10 (7–14)	25	9 (3–27)	148	12 (7–22)	392	10 (7–14)
1984–1988	337	8 (5–13)	558	11 (8–15)	16	27 (12–58)	177	6 (3–13)	446	14 (10–19)
1989–1993	385	10 (7–15)	442	11 (7–16)	21	27 (12–58)	184	11 (7–18)	536	12 (9–17)
1994–1998	467	4 (3–7)	470	19 (15–25)	23	9 (3–25)	220	8 (5–14)	487	15 (11–20)
1999–2003	519	7 (5–10)	380	20 (16–25)	16	9 (3–25)	253	9 (6–13)	575	14 (11–17)

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

0(·-·) No patients survived five years.

Table II. Trends in 5-year age-specific relative survival in percent after oesophageal cancer by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	13	14	2	3	4	*	0	0	12	7	3	0
1969–1973	0	5	2	4	0	0	17	17	6	11	0	0
1974–1978	7	1	1	1	0	0	6	6	7	5	2	0
1979–1983	7	3	7	6	9	0	10	10	10	5	0	0
1984–1988	8	2	2	1	0	0	12	12	6	7	6	0
1989–1993	6	5	6	1	0	0	17	17	11	8	2	0
1994–1998	4	7	7	2	0	0	8	8	4	3	2	0
1999–2003	8	8	8	3	1	0	11	11	11	2	5	0
Finland
1964–1968	21	4	3	2	0	*	10	10	6	3	0	0
1969–1973	16	3	6	4	0	*	15	15	11	4	0	0
1974–1978	12	9	6	1	0	0	14	14	9	5	1	0
1979–1983	27	7	7	4	0	*	22	22	6	6	3	0
1984–1988	12	9	10	6	0	0	13	13	14	9	3	0
1989–1993	6	7	6	8	0	0	17	17	15	5	3	0
1994–1998	8	8	10	8	0	*	33	33	24	9	3	0
1999–2003	14	10	8	9	3	0	30	30	29	9	4	0
Iceland
1964–1968	0	0	0	*	0	*	11	11	11	8	*	*
1969–1973	0	0	0	*	0	*	11	11	11	8	*	*
1974–1978	21	21	19	11	*	*	13	13	13	0	11	*
1979–1983	21	21	19	11	*	*	13	13	13	0	11	*
1984–1988	26	26	19	20	*	*	40	40	40	15	0	*
1989–1993	26	26	19	20	*	*	40	40	40	15	0	*
1994–1998	18	18	10	7	13	*	7	7	7	19	0	*
1999–2003	18	18	10	7	13	*	7	7	7	19	*	*
Norway
1964–1968	9	5	2	1	5	*	6	6	6	6	6	0
1969–1973	0	6	1	3	0	*	0	0	0	7	7	*
1974–1978	0	5	4	3	4	119	0	0	19	5	0	*
1979–1983	0	4	5	2	7	0	19	19	7	7	16	0
1984–1988	0	2	5	5	3	0	6	6	10	6	0	0
1989–1993	4	5	4	6	0	*	8	8	13	14	7	0
1994–1998	13	10	7	7	4	0	7	7	14	5	5	0
1999–2003	20	8	8	6	3	0	10	10	10	9	6	0
Sweden
1964–1968	9	5	5	2	4	0	16	15	9	8	2	0
1969–1973	23	6	3	4	4	0	20	19	11	2	6	0
1974–1978	6	5	6	6	2	0	0	6	10	7	4	0
1979–1983	8	6	4	8	0	*	0	16	12	13	3	0
1984–1988	13	4	8	3	4	0	34	31	3	9	6	0
1989–1993	12	9	7	9	0	0	17	11	17	11	2	0
1994–1998	23	11	12	10	3	0	20	19	14	16	4	0
1999–2003	20	12	13	10	4	29	28	22	9	13	1	0

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Stomach cancer

Incidence and mortality. Age-standardised incidence and mortality rates of stomach cancer have declined steadily in each of the Nordic countries during the four decades studied, irrespective of sex (Figure 3). In absolute terms, the largest reductions (in both incidence and mortality) were seen among men in Finland and Iceland, but the decline among Norwegian men appeared less steep relative to the other populations. A progressive convergence in these rates was seen with time, with a 1.5-fold variation between countries in incidence and mortality circa 2003, with the highest sex-specific rates in Finland and Iceland, and lowest in Sweden and Denmark. The incidence rate in the Nordic countries was around eight per 100 000 in men and four in women; mortality was slightly lower at almost six and three per 100 000, respectively.

Figure 3. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for stomach cancer by sex and country. Nordic cancer survival study 1964–2003.

Survival. For patients diagnosed 1969–1973 in the Nordic countries, age-standardised 5-year relative survival varied from around 10 to 15% compared with a wider range, 15 to 30%, in the latest diagnostic period (Table III). Varying increases in 5-year survival were observed over time in Finland, Iceland, Norway and Sweden. Finland showed the greatest rise in survival in absolute terms over the 40-year period, with the relative survival of 7% for both sexes in the period 1964–1968 increasing to 26% and 30% for men and women diagnosed between 1999 and 2003. Survival was lower in Denmark and increase in survival over time appeared quite modest or non-existent (Figure 3). Lower survival ratios in Denmark were seen for all ages (Table IV) and appeared to be related to a relatively poorer prognosis of patients within the first year after diagnosis (data partially shown, Figure 4). Only minor variation in excess death rates between the Nordic populations was observed 2–5 years after initial diagnosis.

Figure 4. Trends in age-standardised (ICSS) excess death rates per 100 person years for stomach cancer by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003.

Table III. Trends in survival for stomach cancer by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1968	3 402	12 (11–13)	4 292	7 (7–8)	223	14 (9–21)	3 853	11 (10–13)	7 066	11 (11–12)
1969–1973	3 389	11 (10–12)	3 717	11 (10–12)	210	12 (8–19)	3 324	13 (12–14)	6 470	12 (11–13)
1974–1978	3 037	11 (10–12)	3 323	13 (11–14)	191	16 (11–23)	3 051	17 (16–19)	5 546	13 (12–14)
1979–1983	2 777	12 (10–13)	3 085	16 (15–18)	192	24 (19–32)	2 939	18 (17–20)	5 148	16 (15–18)
1984–1988	2 271	12 (11–14)	2 886	20 (18–22)	189	17 (11–24)	2 661	19 (17–21)	4 613	18 (16–19)
1989–1993	1 785	13 (12–15)	2 501	21 (19–23)	173	30 (23–40)	2 437	19 (17–21)	4 172	18 (17–20)
1994–1998	1 628	13 (12–15)	2 291	24 (22–26)	129	26 (19–37)	2 077	18 (16–20)	3 497	20 (18–22)
1999–2003	1 578	14 (12–15)	2 006	26 (24–27)	111	22 (16–31)	1 766	20 (18–22)	3 039	20 (18–21)
Women
1964–1968	2 061	11 (9–12)	3 329	7 (6–9)	111	10 (5–18)	2 483	10 (9–12)	4 419	12 (11–14)
1969–1973	2 121	11 (9–12)	2 925	12 (10–13)	97	21 (13–33)	2 140	11 (10–13)	4 123	13 (12–14)
1974–1978	1 995	12 (10–14)	2 702	13 (12–15)	107	22 (14–33)	1 978	16 (14–18)	3 520	15 (13–16)
1979–1983	1 730	14 (12–16)	2 779	18 (16–20)	94	32 (22–45)	1 982	21 (19–23)	3 182	17 (16–19)
1984–1988	1 504	14 (12–17)	2 658	20 (18–22)	88	41 (30–54)	1 801	23 (21–25)	3 036	20 (19–22)
1989–1993	1 214	16 (14–19)	2 234	24 (22–27)	103	27 (18–39)	1 558	23 (21–26)	2 612	20 (18–22)
1994–1998	1 008	15 (13–18)	1 962	30 (28–33)	67	29 (19–46)	1 370	25 (22–28)	2 220	23 (21–25)
1999–2003	891	14 (12–16)	1 660	30 (28–33)	73	43 (33–56)	1 136	24 (22–27)	2 015	24 (22–26)

Table IV. Trends in 5-year age-specific relative survival in percent after stomach cancer by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	19	14	12	11	7	0	11	13	11	11	7	0
1969–1973	16	13	11	9	7	0	9	12	12	10	8	23
1974–1978	20	13	12	9	5	0	19	13	10	13	7	0
1979–1983	15	15	14	8	7	0	25	17	14	12	7	12
1984–1988	12	19	13	11	6	11	9	19	17	15	7	0
1989–1993	20	15	15	12	7	0	14	19	24	12	7	0
1994–1998	16	20	14	11	7	0	22	27	15	9	8	0
1999–2003	19	16	15	12	7	13	11	20	18	10	8	1
Finland
1964–1968	12	14	8	5	0	0	13	9	8	5	4	0
1969–1973	15	17	10	9	4	39	19	17	11	10	5	0
1974–1978	19	16	15	10	5	0	19	18	14	9	7	0
1979–1983	19	28	17	12	7	0	29	23	18	15	8	7
1984–1988	27	25	22	17	11	0	29	28	22	16	9	0
1989–1993	24	33	20	17	12	0	31	29	28	22	12	0
1994–1998	29	28	24	24	15	19	41	37	33	24	21	18
1999–2003	29	26	27	26	18	13	38	44	34	24	17	11
Iceland
1964–1968	23	23	12	9	12	*	6	6	15	12	*	*
1969–1973	19	19	11	8	10	0	26	26	16	24	14	*
1974–1978	17	17	13	23	6	*	26	26	17	30	6	*
1979–1983	28	28	39	19	*	*	51	51	31	29	*	*
1984–1988	20	20	26	10	7	0	68	68	46	17	24	0
1989–1993	38	38	35	15	37	0	27	27	24	40	6	0
1994–1998	34	34	26	24	16	*	28	28	29	34	23	0
1999–2003	25	25	21	27	12	*	49	49	47	48	12	0
Norway
1964–1968	15	14	13	10	7	0	11	13	14	9	4	0
1969–1973	17	17	13	10	9	0	10	15	12	11	7	0
1974–1978	23	25	18	13	10	0	22	20	14	17	8	0
1979–1983	29	26	17	16	10	0	33	24	22	17	13	0
1984–1988	22	23	22	15	14	0	31	27	23	22	13	13
1989–1993	26	23	22	17	8	24	28	27	25	20	19	14
1994–1998	17	21	22	17	10	0	26	23	31	23	21	24
1999–2003	27	26	22	15	11	0	34	22	27	21	20	8
Sweden
1964–1968	13	17	11	10	7	0	14	11	14	13	11	6
1969–1973	15	15	12	10	7	0	12	18	11	13	10	0
1974–1978	18	18	13	11	6	0	19	17	17	13	9	12
1979–1983	26	18	18	13	9	0	21	17	20	16	11	5
1984–1988	23	22	19	15	11	0	28	23	24	16	14	0
1989–1993	21	25	20	16	11	0	28	24	18	21	12	4
1994–1998	24	23	22	18	14	0	30	25	27	19	16	4
1999–2003	23	25	21	19	11	7	29	23	28	22	15	1

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Cancer of small intestine

Incidence and mortality. Cancer of the small intestine is rare with an age-standardised rate of 0.6–1.7 per 100 000 in 1999–2003. It increased slightly in Sweden, Norway, and Finland over calendar time, with a higher increase among men than women. The incidence in Sweden was double that of Finland and Norway circa 1964 but a steep and continuing increase in Norway from circa 1994 has placed Norway at the top. In 1964 the incidence in Denmark was at the same level as in Sweden, or a bit lower (women), but the Danish incidence remained stable (women) or slightly declining (men). Only a marginal increase in mortality was seen with hardly any difference between countries (Figure 5). Overall, the relative magnitude of rates is more homogenous across countries for mortality than for incidence.

Figure 5. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for cancer of small intestine by sex and country. Nordic cancer survival study 1964–2003.

Survival. Survival was at similar levels and increased in Finland, Norway and Sweden from about 35% in 1964–1968 to 50–55% in 1999–2003, while the Danish survival was at a lower level, beginning at around 18% and reaching 35%, nearly 15 to 20 percent units below the other countries for patients diagnosed with small intestinal cancer 1999–2003 (Table V). The excess mortality in the first month after diagnosis steeply decreased up until 1980 in all countries except Finland (men), which had lower excess death rates than the other countries from the 1960s (Figure 6). For excess mortality 1–3 months after diagnosis the trend was rather stable albeit at a higher level in Denmark than in the other countries. From 2–5 years after diagnosis there have not been any changes to the excess mortality figures; all countries are at a very low level. Due to small numbers it is challenging to draw any conclusions regarding the age-specific 5-year relative survival, but the general pattern is that it increases with time but decreases with age (Table VI).

Figure 6. Trends in age-standardised (ICSS) excess death rates per 100 person years for cancer of small intestine by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003. No Icelandic curves. Too few patients to calculate survival for Iceland.

Table V. Trends in survival for cancer of small intestine by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1968	109	17 (11–26)	50	42 (25–70)	0	*	60	31 (23–41)	280	26 (21–32)
1969–1973	134	19 (13–28)	68	42 (25–70)	8	*	69	31 (23–41)	313	26 (22–32)
1974–1978	165	19 (14–27)	72	37 (28–49)	7	*	86	29 (18–47)	296	40 (33–47)
1979–1983	153	22 (16–32)	104	37 (28–49)	6	*	116	40 (30–52)	336	43 (37–51)
1984–1988	151	24 (17–34)	139	52 (40–68)	8	*	132	32 (24–44)	475	40 (35–45)
1989–1993	125	30 (22–41)	149	42 (32–54)	8	*	143	45 (35–56)	448	44 (38–50)
1994–1998	149	35 (26–46)	167	43 (35–53)	7	*	187	50 (42–61)	482	50 (45–55)
1999–2003	148	35 (28–44)	202	54 (47–61)	16	*	244	48 (42–55)	558	52 (48–56)
Women
1964–1968	83	18 (11–30)	56	35 (28–44)	0	*	46	33 (24–44)	264	32 (26–38)
1969–1973	113	26 (19–37)	77	35 (28–44)	3	*	78	33 (24–44)	299	37 (32–44)
1974–1978	143	22 (16–30)	87	42 (33–54)	7	*	91	45 (32–62)	277	36 (30–43)
1979–1983	146	24 (18–33)	101	53 (42–67)	3	*	120	39 (30–50)	301	48 (42–55)
1984–1988	112	19 (12–29)	132	38 (30–48)	3	*	135	32 (24–42)	392	42 (37–47)
1989–1993	134	27 (19–37)	153	38 (31–47)	7	*	157	40 (33–50)	397	48 (43–54)
1994–1998	136	19 (13–28)	159	47 (39–56)	13	*	155	47 (39–57)	468	47 (42–52)
1999–2003	151	35 (28–43)	174	49 (43–56)	10	*	242	55 (49–61)	427	51 (47–55)

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Table VI. Trends in 5-year age-specific relative survival in percent after cancer of small intestine by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	46	12	17	17	0	*	30	24	21	18	0	*
1969–1973	36	37	14	8	14	*	40	35	34	22	0	*
1974–1978	11	32	30	16	0	*	42	52	28	3	0	*
1979–1983	41	21	25	18	12	*	34	33	22	24	11	*
1984–1988	25	30	26	19	21	*	23	15	31	11	14	*
1989–1993	77	41	7	24	35	*	36	35	25	23	20	*
1994–1998	44	50	33	16	48	*	23	19	30	12	12	*
1999–2003	58	48	22	26	41	*	56	38	43	25	19	11
Finland
1964–1968	41	50	32	34	69	*	60	33	37	41	0	*
1969–1973	41	50	32	34	69	*	60	33	37	41	0	*
1974–1978	45	43	32	42	23	*	54	64	48	41	0	*
1979–1983	45	43	32	42	23	*	74	51	45	48	63	*
1984–1988	68	47	40	33	103	*	50	32	56	33	9	*
1989–1993	44	55	39	33	46	*	63	60	43	27	8	*
1994–1998	52	56	43	46	16	*	67	67	48	36	26	0
1999–2003	77	63	64	45	23	*	67	63	50	47	21	0
Iceland
1964–1968	23	23	23	*	*	*	*	*	*	*		*
1969–1973	23	23	23	*	*	*	*	*	*	*	*	*
1974–1978	41	41	41	24	*	*	*	*	*	*	*	*
1979–1983	41	41	41	24	*	*	*	*	*	*	*	*
1984–1988	88	88	88	*	*	*	*	*	*	*	*	*
1989–1993	88	88	88	*	*	*	*	*	*	*	*	*
1994–1998	62	62	62	19	*	*	70	70	70	*	*	*
1999–2003	62	62	62	19	*	*	70	70	70	*	*	*
Norway
1964–1968	42	37	29	40	0	*	61	33	40	20	22	*
1969–1973	42	37	29	40	0	*	61	33	40	20	22	*
1974–1978	31	25	35	5	65	*	78	32	48	22	69	*
1979–1983	41	38	59	29	28	*	54	51	34	37	25	*
1984–1988	59	41	21	21	43	*	36	37	48	24	10	*
1989–1993	46	41	52	44	35	*	62	47	36	38	28	*
1994–1998	64	48	51	43	54	*	64	31	63	36	45	*
1999–2003	45	62	54	44	34	*	61	63	65	47	38	48
Sweden
1964–1968	34	51	28	15	7	*	43	50	34	21	19	*
1969–1973	47	44	22	23	5	*	65	44	32	33	24	*
1974–1978	58	41	38	43	19	*	61	28	40	34	23	*
1979–1983	59	47	48	45	15	*	63	46	47	52	34	*
1984–1988	60	61	46	24	21	*	61	54	40	36	26	0
1989–1993	48	59	43	33	44	105	56	54	55	41	37	73
1994–1998	60	59	55	44	31	118	67	54	51	43	23	0
1999–2003	64	61	51	47	44	55	76	61	53	45	27	0

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Colon cancer

Incidence and mortality. The incidence of colon cancer has been increasing among men in the Nordic countries, most notably in Norway (Figure 7). Whereas male incidence rates in Denmark were historically the highest, rates in Norway and Iceland surpassed them in the 1980s. Among Norwegian and Finnish women, colon cancer incidence increased in parallel to that in men, whilst the incidence among Danish, Icelandic and Swedish women remained stable. Colon cancer mortality, on the other hand, declined but remained highest among Danish men, increased to some extent in Norway and Iceland, decreased in Sweden, and remained stable in Finland. Rates in women shared similar temporal patterns, particularly in the last two decades under study.

Figure 7. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for colon cancer by sex and country. Nordic cancer survival study 1964–2003.

Survival. The age-standardised 5-year relative survival increased in the observed period for all Nordic countries and in both sexes (Figure 7 and Table VII), and ranged from 50 to 60% in 1999–2003. Throughout the period from 1969 to 2003 the Danish survival was lower than in the other Nordic countries. Finland had the lowest survival among the Nordic countries in 1964–1968 but as a result of rapid survival increases observed thereafter, Finnish patients had the highest survival in both sexes in 1999–2003. The fluctuation of the Icelandic survival curve was due to the small population size, but the survival trends were fairly similar to those seen in Sweden, Finland and Norway. Studying the excess deaths by time since diagnosis, the rates were higher among Danish men and women within the first three months after diagnosis, although in all countries excess mortality was halved over the four decades. Beyond two years after diagnosis the excess mortality was similar in all Nordic countries (Figure 8).

Figure 8. Trends in age-standardised (ICSS) excess death rates per 100 person years for colon cancer by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003.

Table VII. Trends in survival for colon cancer by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1969	2 556	31 (29–34)	750	24 (21–28)	54	41 (27–61)	1 708	33 (30–35)	4 719	35 (33–37)
1969–1973	3 125	30 (28–32)	940	35 (31–40)	67	41 (28–60)	1 803	38 (35–41)	5 318	36 (35–38)
1974–1978	3 695	34 (32–36)	1 103	37 (33–41)	84	47 (36–61)	2 314	42 (40–45)	5 323	39 (37–41)
1979–1983	3 737	37 (35–39)	1 501	48 (45–51)	128	47 (38–58)	2 915	47 (45–50)	5 777	46 (44–48)
1984–1988	4 137	39 (37–41)	1 836	47 (44–50)	152	42 (33–53)	3 443	46 (44–48)	6 337	48 (47–50)
1989–1993	4 275	43 (41–45)	2 099	51 (48–54)	145	57 (48–68)	3 988	49 (47–51)	6 802	52 (50–53)
1994–1998	4 521	45 (43–47)	2 651	57 (54–59)	203	51 (43–61)	4 322	53 (51–55)	7 214	55 (54–57)
1999–2003	5 199	49 (47–50)	2 969	59 (57–61)	238	55 (49–62)	4 784	55 (54–57)	7 761	56 (55–57)
Women
1964–1969	3 269	33 (31–35)	1 169	30 (27–33)	67	32 (21–50)	1 946	34 (32–37)	4 919	38 (37–40)
1969–1973	3 791	35 (33–36)	1 496	35 (33–38)	93	36 (26–48)	2 215	39 (37–42)	5 690	39 (37–40)
1974–1978	4 530	35 (34–37)	1 827	40 (37–42)	106	53 (43–65)	2 890	42 (40–45)	5 760	42 (40–43)
1979–1983	4 955	41 (39–43)	2 342	46 (43–48)	114	54 (43–66)	3 602	47 (45–49)	6 591	49 (47–50)
1984–1988	5 172	43 (41–44)	2 675	51 (48–53)	138	49 (40–60)	4 117	51 (49–53)	7 068	52 (51–54)
1989–1993	5 314	46 (45–48)	3 042	53 (51–56)	150	61 (52–71)	4 483	53 (52–55)	7 537	54 (53–56)
1994–1998	5 447	48 (47–50)	3 399	57 (55–59)	172	50 (42–60)	5 237	57 (55–58)	7 706	56 (55–58)
1999–2003	5 660	52 (51–53)	3 679	62 (61–64)	183	58 (51–65)	5 664	59 (57–60)	8 248	60 (59–61)

The age-specific 5-year relative survival ratios are presented in Table VIII. The general pattern was that survival diminished with increasing age, but increased with time in each age group, with the largest increases in survival seen in patients above the age of 70 at diagnosis. From the late-1960s survival among Danish men and women fell behind the other Nordic countries in all patients diagnosed at ages under 90.

Table VIII. Trends in 5-year age-specific relative survival in percent after colon cancer by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	46	37	30	30	17	0	38	37	36	30	26	13
1969–1973	46	38	30	28	15	0	42	37	38	31	25	49
1974–1978	45	33	36	31	30	0	41	40	40	34	20	16
1979–1983	44	41	39	35	27	12	44	47	44	37	34	20
1984–1988	45	46	41	34	34	31	46	45	46	40	37	37
1989–1993	53	41	45	42	36	39	49	50	49	45	39	34
1994–1998	55	45	45	43	40	39	53	51	50	47	43	46
1999–2003	58	47	52	46	43	24	59	53	53	50	47	42
Finland
1964–1968	39	29	29	21	4	*	45	43	30	21	19	0
1969–1973	50	42	39	29	22	*	56	43	36	30	20	0
1974–1978	50	37	36	36	30	58	58	44	42	35	26	0
1979–1983	59	54	48	50	28	0	66	46	45	43	34	21
1984–1988	54	52	47	42	43	112	73	56	50	45	38	14
1989–1993	63	53	48	48	50	0	73	58	52	48	44	21
1994–1998	68	57	57	55	51	61	71	62	58	55	45	34
1999–2003	68	57	59	59	54	62	73	66	60	62	53	32
Iceland
1964–1968	40	40	58	16	58	*	31	31	46	15	46	*
1969–1973	37	37	34	46	50	*	47	47	26	35	32	*
1974–1978	58	58	63	39	14	*	74	74	51	40	41	*
1979–1983	70	70	59	31	10	*	51	51	49	50	73	*
1984–1988	44	44	45	39	38	*	51	51	55	39	54	0
1989–1993	67	67	57	47	58	109	62	62	66	47	77	137
1994–1998	46	46	55	50	54	63	54	54	43	55	49	91
1999–2003	62	62	66	49	35	128	57	57	63	57	49	101
Norway
1964–1968	50	33	34	30	21	0	39	44	38	30	21	0
1969–1973	37	40	35	37	41	0	51	41	44	36	28	15
1974–1978	56	47	41	42	29	20	54	44	44	40	34	0
1979–1983	56	52	48	45	40	45	51	51	48	49	33	39
1984–1988	52	47	50	45	34	35	54	55	53	51	41	45
1989–1993	44	47	54	47	50	31	57	56	54	54	45	36
1994–1998	55	54	54	52	49	36	58	54	63	55	50	43
1999–2003	57	58	58	52	49	36	60	60	63	57	52	31
Sweden
1964–1968	47	43	36	30	23	20	57	42	40	32	28	23
1969–1973	48	43	37	32	25	6	49	46	42	35	24	14
1974–1978	43	43	41	37	31	15	43	46	44	41	33	15
1979–1983	51	47	48	47	36	30	51	49	50	48	46	21
1984–1988	50	49	48	48	48	56	58	53	52	50	49	38
1989–1993	54	52	51	51	52	50	57	52	53	56	52	38
1994–1998	57	57	56	55	51	39	57	55	56	56	56	65
1999–2003	61	56	55	56	52	72	62	60	60	58	61	60

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Rectal and anal cancer

Incidence and mortality. The incidence of rectal cancer in Denmark was historically the highest among the Nordic countries and was rather constant during the whole period with an incidence among men of 17 and among women 11 per 100 000. Norway started at a relatively low level of around five per 100 000 in 1964, close to those of Iceland, Finland, and Swedish women, while Swedish men had a slightly higher baseline incidence at 11 per 100 000. Norwegian incidence increased steeply to a similar level of that observed in Denmark (Figure 9), while a less rapid increase was observed for Finland and Sweden. The mortality has been decreasing during the whole period at almost the same pace in all countries, except in Norway, where the mortality increased up until the mid-1980s.

Figure 9. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for rectal and anal cancer by sex and country. Nordic cancer survival study 1964–2003.

Survival. Rectal cancer survival increased steadily throughout the observation period. Since the early 1970s there was little difference in relative survival between men in Finland, Norway and Sweden, while Finnish women had a slightly poorer survival than Norwegian and Swedish patients. Survival in Denmark was comparable to the other Nordic countries circa 1964, but subsequently Danish survival did not increase to the same extent as in the other populations. Five-year relative survival after rectal cancer in the Nordic populations varied between 49% and 65% in 1999–2003 and the absolute increases in 5-year survival were between 18 and 34 percent units over the diagnostic period 1964 to 2003 (lower for Icelandic women) (Table IX).

Table IX. Trends in survival for rectal and anal cancer by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1968	2 715	31 (28–33)	791	24 (21–28)	39	32 (21–51)	1 041	27 (24–31)	3 263	33 (31–35)
1969–1973	3 024	32 (30–34)	991	30 (27–34)	37	25 (12–49)	1 451	32 (29–35)	3 522	35 (34–38)
1974–1978	3 266	34 (32–36)	1 220	38 (35–42)	50	34 (22–53)	1 906	37 (35–40)	3 908	38 (36–40)
1979–1983	3 531	35 (33–37)	1 440	40 (37–43)	51	35 (22–53)	2 420	44 (41–47)	4 224	43 (41–45)
1984–1988	3 470	37 (35–39)	1 550	49 (46–52)	61	58 (44–76)	2 606	45 (42–47)	4 518	46 (45–48)
1989–1993	3 562	41 (39–43)	1 800	46 (44–49)	42	54 (38–77)	2 797	48 (46–50)	4 799	51 (49–53)
1994–1998	3 648	45 (43–47)	2 039	54 (51–57)	68	47 (35–62)	2 941	56 (53–58)	4 990	54 (52–56)
1999–2003	3 892	49 (48–51)	2 289	57 (55–59)	77	65 (55–76)	3 171	57 (56–59)	5 339	57 (56–58)
Women
1964–1968	2 030	31 (29–34)	1 010	30 (27–34)	30	45 (32–64)	856	29 (25–32)	2 395	37 (35–39)
1969–1973	2 280	35 (33–37)	1 131	37 (33–40)	42	45 (32–64)	1 212	37 (34–40)	2 680	41 (39–43)
1974–1978	2 484	38 (36–40)	1 331	41 (38–44)	35	44 (29–68)	1 558	42 (40–45)	2 882	43 (41–45)
1979–1983	2 845	41 (39–43)	1 503	44 (41–47)	43	58 (43–79)	1 977	48 (46–51)	3 501	47 (45–49)
1984–1988	2 705	41 (39–43)	1 655	48 (45–51)	47	39 (26–57)	2 078	51 (48–53)	3 719	53 (51–54)
1989–1993	2 793	43 (41–46)	1 729	50 (48–53)	51	61 (48–79)	2 341	57 (54–59)	4 063	55 (54–57)
1994–1998	3 041	50 (48–52)	1 950	55 (52–58)	60	41 (29–56)	2 474	60 (57–62)	4 046	61 (59–63)
1999–2003	3 024	53 (51–54)	2 070	60 (58–62)	81	52 (43–64)	2 553	63 (61–65)	4 290	62 (61–64)

In Figure 10, the curves of excess mortality for different follow-up intervals show that the decrease was most evident within the first month after diagnosis from a level above 100 deaths per 100 person years, and that excess mortality halved over time. The reduction in excess mortality over time continued for the next follow-up intervals until two years after diagnosis (data not shown for three months to two years). For follow-up 2–5 years after diagnosis, the excess rates were stable and at about the same level, at less than 10 excess deaths per 100 person years in all Nordic countries. Age-specific 5-year relative survival increased in successive calendar periods, but was consistently lower for patients aged over 70 years at diagnosis in all countries for both sexes (Table X).

Figure 10. Trends in age-standardised (ICSS) excess death rates per 100 person years for rectal and anal cancer by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003.

Table X. Trends in 5-year age-specific relative survival in percent after rectal and anal cancer by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	43	35	35	25	17	0	40	37	35	29	16	21
1969–1973	42	37	34	30	19	0	44	39	40	31	20	0
1974–1978	33	40	39	35	19	13	49	47	42	33	23	0
1979–1983	42	38	40	34	20	20	50	48	42	40	26	7
1984–1988	39	44	36	38	29	42	45	50	47	39	23	12
1989–1993	48	43	46	38	30	12	52	47	46	40	33	20
1994–1998	52	46	47	44	34	28	57	57	54	47	36	24
1999–2003	52	54	53	47	39	32	61	59	56	50	37	28
Finland
1964–1968	38	29	34	18	4	0	41	37	35	25	16	*
1969–1973	37	46	36	22	11	0	41	44	46	29	21	0
1974–1978	48	48	40	35	22	0	45	62	43	37	18	0
1979–1983	50	44	45	38	23	0	52	48	49	47	17	39
1984–1988	52	50	51	47	46	0	66	53	50	43	33	24
1989–1993	52	48	48	47	37	39	67	53	53	48	34	33
1994–1998	59	57	56	53	47	18	66	69	58	50	36	32
1999–2003	64	59	60	55	48	52	73	68	64	56	44	25
Iceland
1964–1968	52	52	52	12	*	*	36	36	48	37	76	*
1969–1973	22	22	22	22	40	*	36	36	48	37	76	*
1974–1978	38	38	38	34	19	*	62	62	36	56	*	*
1979–1983	45	45	45	23	16	*	65	65	64	61	31	*
1984–1988	67	67	67	46	47	*	56	56	47	25	17	*
1989–1993	52	52	52	70	31	*	71	71	63	67	27	*
1994–1998	55	55	55	43	21	*	66	66	37	21	37	*
1999–2003	73	73	73	52	59	*	65	65	64	33	43	*
Norway
1964–1968	39	33	30	24	13	0	41	32	38	22	11	0
1969–1973	37	37	34	27	29	0	37	47	44	31	25	0
1974–1978	48	43	43	33	21	21	52	49	48	40	22	0
1979–1983	56	46	46	41	35	18	64	62	49	44	28	26
1984–1988	53	52	48	40	32	0	57	62	57	43	38	22
1989–1993	51	54	52	48	33	24	63	69	60	52	40	6
1994–1998	60	62	57	56	42	28	64	69	64	58	42	53
1999–2003	63	64	60	55	47	33	70	71	65	60	50	33
Sweden
1964–1968	43	39	38	28	15	0	49	48	39	34	18	15
1969–1973	45	41	39	30	26	19	60	48	46	35	21	13
1974–1978	49	42	42	34	25	11	52	53	47	40	25	11
1979–1983	53	42	45	43	33	8	62	51	49	44	31	23
1984–1988	54	47	49	45	38	34	62	62	54	48	40	17
1989–1993	54	53	54	51	39	8	59	61	59	54	44	44
1994–1998	55	61	54	54	46	53	70	68	63	58	48	36
1999–2003	61	63	58	54	50	40	72	68	66	58	51	35

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Liver cancer

Incidence and mortality. Incidence trends in liver cancer by country followed a similar pattern among men and women, although the incidence among women was consistently about half that of men (Figure 11). An initial increase in incidence was observed for both sexes in Finland and Sweden between 1960 and 1980, followed by a decrease, most notably in Sweden. The age-standardised incidence varied 2-fold between the countries with the highest incidence in Sweden and lowest in Norway. The liver cancer mortality pattern between countries and over time was largely similar to incidence, but with larger trend shifts during the observed period, especially in Sweden and Denmark.

Figure 11. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for liver cancer by sex and country. Nordic cancer survival study 1964–2003.

Survival. Survival for persons diagnosed with liver cancer was low, and increases over the diagnostic period were quite modest, with the highest 5-year relative survival approaching 11% for Norwegian female patients, while Denmark had the lowest survival, 3% in males and 5% in females in 1999–2003 (Figure 11 and Table XI). The excess mortality declined during the first month after diagnosis from about 800 (men) and 600 (women) deaths per 100 person years to 400 in 1999–2003. Excess mortality 1–3 months after diagnosis also declined, with the highest level in Denmark. In the follow-up period 2–5 years after diagnosis, no systematic variation over time and between the countries was seen (Figure 12). Persons diagnosed with liver cancer before the age of 50 tended to have a higher survival than older persons, while women tended to have a higher survival than men (Table XII).

Figure 12. Trends in age-standardised (ICSS) excess death rates per 100 person years for liver cancer by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003.

Table XI. Trends in survival for liver cancer by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1968	376	1 (0–3)	146	0 (·-·)	12	*	145	0 (·-·)	1 041	2 (1–3)
1969–1973	487	0 (0–1)	244	0 (0–3)	14	*	205	1 (0–4)	1 312	3 (2–4)
1974–1978	590	1 (0–2)	328	2 (1–5)	13	*	252	6 (4–11)	1 042	2 (1–4)
1979–1983	577	2 (1–4)	395	2 (1–5)	13	*	254	1 (0–4)	1 135	1 (1–2)
1984–1988	633	2 (1–4)	525	5 (4–8)	18	14 (6–35)	311	3 (1–5)	1 283	3 (2–5)
1989–1993	615	3 (2–5)	535	4 (3–7)	18	14 (6–35)	289	6 (4–9)	1 350	5 (4–7)
1994–1998	660	4 (2–6)	669	7 (5–10)	28	7 (3–21)	268	5 (3–8)	1 366	6 (5–8)
1999–2003	852	3 (2–4)	670	8 (6–10)	16	7 (3–21)	368	5 (4–8)	1 292	7 (6–8)
Women
1964–1968	269	1 (0–4)	128	1 (0–6)	8	*	71	7 (3–15)	655	2 (1–5)
1969–1973	320	1 (0–4)	199	0 (0–3)	8	*	130	6 (3–12)	896	3 (2–5)
1974–1978	445	1 (0–3)	258	3 (2–7)	14	*	140	3 (1–8)	850	3 (2–5)
1979–1983	478	2 (1–4)	359	3 (2–6)	15	*	170	3 (1–8)	856	3 (2–5)
1984–1988	444	4 (2–7)	456	5 (3–9)	7	*	205	10 (6–17)	995	3 (2–5)
1989–1993	475	3 (1–5)	492	5 (3–8)	11	*	219	8 (5–13)	1 087	3 (2–5)
1994–1998	453	4 (2–6)	437	7 (4–11)	10	*	165	11 (6–18)	1 047	7 (5–9)
1999–2003	511	5 (3–7)	464	8 (6–11)	8	*	237	11 (8–16)	852	8 (6–9)

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18]. 0 (·-·) No patients survived five years.

Table XII. Trends in 5-year age-specific relative survival in percent after liver cancer by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	9	0	0	0	0	*	5	0	0	3	0	*
1969–1973	0	0	1	0	0	*	0	2	1	0	3	*
1974–1978	5	0	0	1	0	0	0	2	2	0	2	*
1979–1983	9	0	1	2	0	0	3	2	1	2	2	0
1984–1988	7	1	2	0	2	0	24	2	2	0	0	0
1989–1993	16	0	2	2	0	0	5	7	2	2	0	0
1994–1998	16	4	3	0	3	0	8	6	4	2	0	0
1999–2003	7	5	3	1	1	0	18	8	5	0	1	0
Finland
1964–1968	0	0	0	0	0	*	7	0	2	0	0	*
1969–1973	3	0	0	0	0	*	4	0	0	0	0	*
1974–1978	10	2	0	2	0	*	5	3	5	3	0	0
1979–1983	8	2	2	2	0	*	8	3	4	2	0	0
1984–1988	26	3	3	4	0	0	17	7	5	3	0	0
1989–1993	16	7	2	2	0	61	21	5	2	4	0	0
1994–1998	14	4	7	7	4	0	7	18	6	4	0	0
1999–2003	14	7	8	6	5	0	14	11	9	5	2	0
Iceland
1964–1968	0	0	0	0	*	*	*	*	*	*	*	*
1969–1973	0	0	0	0	*	*	*	*	*	*	*	*
1974–1978	0	0	0	0	0	*	30	30	30	*	*	*
1979–1983	0	0	0	0	0	*	30	30	30	*	*	*
1984–1988	12	12	12	26	0	*	11	11	11	*	*	*
1989–1993	12	12	12	26	0	*	11	11	11	*	*	*
1994–1998	10	10	10	7	0	*	8	8	8	*	*	*
1999–2003	10	10	10	7	0	*	8	8	8	*	*	*
Norway
1964–1968	0	0	0	0	0	*	34	0	10	0	0	*
1969–1973	8	3	0	0	0	*	16	0	12	2	0	*
1974–1978	29	0	3	3	8	*	13	6	0	0	0	*
1979–1983	4	0	0	2	0	*	14	0	0	0	6	*
1984–1988	13	0	2	1	0	0	33	14	9	5	0	0
1989–1993	34	0	3	4	0	*	37	9	4	3	0	*
1994–1998	19	3	2	5	0	*	37	11	13	2	0	0
1999–2003	17	7	4	3	0	0	34	12	12	6	0	0
Sweden
1964–1968	5	2	1		1	0	4	5	1	1	4	0
1969–1973	15	1	2		0	0	9	5	1	2	2	16
1974–1978	7	1	3		0	0	8	6	1	3	0	0
1979–1983	5	2	0		0	0	13	1	2	2	0	0
1984–1988	10	4	1		2	0	11	4	3	2	1	0
1989–1993	18	7	3	2	2	0	10	3	2	2	0	0
1994–1998	19	7	5	2	3	0	24	8	4	4	2	0
1999–2003	20	9	6	3	4	0	26	12	4	3	4	0

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Cancer of the gallbladder and extrahepatic biliary ducts

Incidence and mortality. Historically cancer of the gallbladder and extrahepatic biliary ducts (“gallbladder”) was more common in women than in men in the Nordic countries, but in recent years the incidence rates did not differ markedly. Variation between countries was larger among women (range 1.2–2.5 per 100 000) than men (1.4–1.9). In Finland and Sweden incidence peaked around 1980 and declined afterwards, while in Denmark decrease started in the mid-1970s. Norway and Iceland had the lowest incidence, slightly increasing over time for men and stable among women (Figure 13). In general, mortality trends followed the incidence patterns, although mortality was higher than incidence in Sweden from the mid-1990s (Figure 13).

Figure 13. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for cancer of the gallbladder and extrahepatic biliary ducts by sex and country. Nordic cancer survival study 1964–2003.

Survival. Survival was rather low for gallbladder cancer patients, but increased slightly over time. Five-year relative survival in 1999–2003 variedfrom 10 to 14% in Denmark, Finland, Norway, and Sweden. Norwegian female patients, and to some extent male patients, had increased survival during the 1980s, although the survival ratios appeared to decline to the same level as the other countries thereafter. Patients in Denmark and Sweden had the largest reduction in excess mortality over time within the first month after diagnosis, as well as during the interval 1 to 3 months, particularly among males. Excess mortality differed more substantially between the countries in the 1960s than in the most recent period, but the contemporary mortality levels were higher at approximately 200 deaths per 100 person years in women in the first three months after diagnosis for the period 1999–2003. The corresponding male figures were 150–250 per 100 person years (Figure 14).

Figure 14. Trends in age-standardised (ICSS) excess death rates per 100 person years for cancer of the gallbladder and extrahepatic bilary ducts by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003.

Studying age-specific relative survival revealed that the younger patients, aged below 50 years, had higher and increasing survival, especially among women. The 5-year relative survival proportion was however only 30% and 29% in Iceland and Denmark, respectively, the countries with the highest survival, and was lowest in Sweden at 16% (Table XIV).

Table XIII. Trends in survival for cancer of gallbladder and extrahepatic biliary ducts by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1968	325	4 (2–7)	120	5 (3–8)	2	*	127	4 (2–9)	681	5 (3–8)
1969–1973	423	2 (1–5)	171	5 (3–8)	6	*	128	4 (2–9)	789	6 (4–9)
1974–1978	429	5 (3–8)	209	9 (5–14)	9	*	179	10 (5–19)	842	8 (6–11)
1979–1983	381	6 (3–10)	314	6 (3–10)	10	*	172	8 (4–15)	883	6 (4–8)
1984–1988	369	7 (5–12)	347	7(5–11)	10	*	226	15 (10–21)	976	9 (7–12)
1989–1993	345	8 (5–12)	335	10 (7–14)	12	*	198	12 (8–20)	861	10 (8–13)
1994–1998	317	10 (7–14)	394	9 (6–13)	12	17 (8–38)	275	12 (8–18)	729	12 (10–16)
1999–2003	319	10 (8–14)	378	13 (10–17)	17	17 (8–38)	275	14 (11–19)	656	13 (11–16)
Women
1964–1968	647	2 (1–4)	343	3 (1–5)	10	*	262	4 (2–7)	1 458	4 (3–5)
1969–1973	889	5 (3–8)	479	5 (3–8)	15	*	274	8 (5–13)	1 852	5 (3–6)
1974–1978	930	4 (3–7)	682	5 (3–8)	11	12 (2–58)	283	7 (5–12)	1 838	4 (3–6)
1979–1983	839	6 (4–9)	892	7 (6–10)	10	12 (2–58)	369	12 (9–18)	1 921	6 (5–8)
1984–1988	752	5 (3–7)	997	9 (7–12)	18	31 (17–56)	373	21 (16–28)	2 030	5 (4–7)
1989–1993	603	8(5–11)	895	9 (7–12)	19	31 (17–56)	307	10 (6–17)	1 772	9 (7–10)
1994–1998	477	7 (4–11)	888	13 (10–16)	30	29 (17–48)	363	13 (9–19)	1 381	9 (7–11)
1999–2003	460	11 (8–16)	836	12 (10–14)	14	29 (17–48)	381	12 (9–16)	1 154	10 (9–12)

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Table XIV. Trends in 5-year age-specific relative survival in percent after cancer of gallbladder and extrahepatic biliary ducts by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	4	14	3	0	0	*	0	4	2	2	2	0
1969–1973	0	10	1	1	0	0	11	8	5	4	1	0
1974–1978	9	7	4	3	3	0	11	4	5	3	2	0
1979–1983	11	8	7	2	4	*	14	9	7	4	1	0
1984–1988	24	10	2	6	4	0	5	8	5	2	5	0
1989–1993	13	8	9	6	3	*	18	12	6	5	2	0
1994–1998	0	24	8	10	4	*	17	10	6	3	1	15
1999–2003	10	17	13	9	1	0	29	23	10	3	3	31
Finland
1964–1968	7	5	8	3	0	*	0	6	5	1	0	*
1969–1973	7	5	8	3	0	*	13	8	5	4	0	*
1974–1978	8	18	8	10	0	*	16	5	4	3	0	0
1979–1983	10	11	3	4	6	*	9	12	9	5	2	35
1984–1988	5	7	14	3	4	*	22	12	8	7	4	0
1989–1993	12	16	13	7	0	*	19	11	7	9	2	0
1994–1998	16	11	9	8	2	52	23	10	19	9	5	0
1999–2003	26	22	9	9	6	16	21	13	15	7	5	0
Iceland
1964–1968	0	0	0	*	*	*	11	11	11	10	*	*
1969–1973	0	0	0	*	*	*	11	11	11	10	*	*
1974–1978	10	10	10	0	*	*	0	0	0	41	0	*
1979–1983	10	10	10	0	*	*	0	0	0	41	0	*
1984–1988	0	0	0	*	26	*	35	35	35	30	17	*
1989–1993	0	0	0	*	26	*	35	35	35	30	17	*
1994–1998	23	23	23	9	12	*	30	30	30	37	8	*
1999–2003	23	23	23	9	12	*	30	30	30	37	8	*
Norway
1964–1968	11	3	8	0	0	*	0	4	5	6	0	*
1969–1973	11	3	8	0	0	*	18	8	9	2	7	*
1974–1978	20	6	11	7	9	*	8	3	10	9	3	*
1979–1983	0	23	7	6	0	*	28	7	16	9	7	39
1984–1988	17	15	24	9	5	*	67	19	26	9	2	0
1989–1993	21	22	7	12	5	*	29	9	13	2	6	0
1994–1998	23	18	14	6	3	*	25	22	10	10	6	0
1999–2003	22	18	15	13	3	*	26	15	11	10	3	0
Sweden
1964–1968	15	7	4	4	0	0	7	7	3	3	1	0
1969–1973	12	13	5	3	2	0	6	8	3	5	1	0
1974–1978	11	12	9	4	5	0	8	7	4	4	1	0
1979–1983	8	6	6	6	3	0	10	8	7	4	4	0
1984–1988	25	13	6	7	3	0	5	7	6	5	2	6
1989–1993	12	15	12	9	3	0	7	11	10	8	5	0
1994–1998	14	19	16	7	7	0	12	13	8	8	4	0
1999–2003	22	18	16	8	6	2	16	13	10	9	4	0

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Cancer of pancreas

Incidence and mortality. The incidence of pancreatic cancer was higher among males than females through most of the observed period. For males, there was an increasing trend until the early-1970s, when incidence reached a plateau of around 9–10 per 100 000, before starting to decline from the mid-1980s. Up to the mid-1980s the incidence was lower in Norway and Sweden, followed by a more pronounced decrease in Sweden than in the other countries. In each of the Nordic countries the trend either stabilised or increased again from the mid-1990s, with the most pronounced increase observed in Denmark. The unstable Icelandic incidence rates reflect the small population but follow the general pattern of the Nordic countries (Figure 15). In general, the mortality rates closely followed those of incidence, although in Sweden the number of pancreatic cancer deaths exceeded the number of incident cases.

Figure 15. Trends in age-standardised (World) incidence and mortality rates per 100 000 and age-standardised (ICSS) 5-year relative survival for cancer of pancreas by sex and country. Nordic cancer survival study 1964–2003.

Survival. There has been little change in survival for patients diagnosed with pancreas cancer over the consecutive diagnostic periods (Figure 15), with 5-year survival quite stable at around 3–5% (compared to 0–3% in the 1960s), with little variation between the countries (Table XV). However, some declines in excess mortality were noted in the first three months after diagnosis. The excess mortality was highest in Denmark in the follow-up interval 1–3 months. The excess mortality rates were low and reasonably stable over time and between countries 2–5 years after diagnosis (Figure 16).

Figure 16. Trends in age-standardised (ICSS) excess death rates per 100 person years for cancer of pancreas by sex, country, and time since diagnosis. Nordic cancer survival study 1964–2003.

Table XV. Trends in survival for cancer of pancreas by sex and country. Number of tumours (N) included and the 5-year age-standardised (ICSS) relative survival in percent with 95% confidence intervals (RS (CI)). Nordic cancer survival study 1964–2003.

	Denmark		Finland		Iceland		Norway		Sweden
	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)	N	RS (CI)
Men
1964–1968	1 288	2 (1–3)	905	0 (0–1)	37	0 (·-·)	986	2 (1–3)	2 553	3(2–4)
1969–1973	1 689	2 (1–3)	1 033	1 (1–2)	42	0 (·-·)	1 181	1 (1–3)	2 966	4 (3–4)
1974–1978	1 796	1 (1–2)	1 191	2 (1–3)	59	2 (0–13)	1 249	2 (1–3)	2 552	3(2–4)
1979–1983	1 718	3 (2–4)	1 279	2 (1–4)	58	0 (·-·)	1 377	1 (1–2)	2 570	3(2–4)
1984–1988	1 694	2 (2–3)	1 467	3 (2–4)	74	1 (0–10)	1 434	2 (1–3)	2 628	3(3–4)
1989–1993	1 466	2 (2–3)	1 456	3 (2–4)	67	4 (1–16)	1 317	2 (2–4)	2 341	2 (2–4)
1994–1998	1 493	3 (2–4)	1 622	3 (2–4)	68	0 (·-·)	1 324	2(1–4)	2 155	4 (3–5)
1999–2003	1 728	3 (2–3)	1 758	3 (2–4)	73	3 (1–9)	1 408	3 (3–5)	2 007	4 (4–5)
Women
1964–1968	953	2 (1–3)	777	1 (1–2)	44	3 (0–21)	658	2 (1–3)	2 071	3(2–4)
1969–1973	1 400	2 (1–3)	1 003	2 (1–4)	35	0 (·-·)	859	2(1–4)	2 374	3 (3–5)
1974–1978	1 525	1 (1–2)	1 153	2 (1–3)	42	2 (0–14)	968	2(1–4)	2 257	3(2–4)
1979–1983	1 798	1 (1–2)	1 446	2 (1–4)	58	7 (3–21)	1 167	3 (2–4)	2 397	3(2–4)
1984–1988	1 686	2 (1–3)	1 695	4 (3–6)	56	0 (·-·)	1 402	2 (2–4)	2 665	4 (3–5)
1989–1993	1 669	2 (1–3)	1 913	3 (2–4)	63	4 (1–17)	1 307	3 (2–5)	2 697	4 (3–5)
1994–1998	1 652	3 (2–4)	1 913	3 (2–5)	79	3 (1–13)	1 500	4 (3–6)	2 427	5 (4–6)
1999–2003	1 902	3 (3–4)	2 135	4 (3–5)	63	1 (0–5)	1 576	4 (3–5)	2 143	5 (4–6)

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18]. 0 (·-·) No patients survived five years.

Table XVI. Trends in 5-year age-specific relative survival in percent after cancer of pancreas by sex and country. Nordic cancer survival study 1964–2003.

	Men						Women
Age	0–49	50–59	60–69	70–79	80–89	90+	0–49	50–59	60–69	70–79	80–89	90+
Denmark
1964–1968	4	0	2	2	2	0	0	3	1	2	2	0
1969–1973	1	2	1	2	2	0	1	2	1	3	1	0
1974–1978	0	4	1	1	1	0	2	2	1	1	1	0
1979–1983	5	1	2	2	4	0	4	2	0	1	0	18
1984–1988	5	3	2	1	3	0	5	3	3	1	0	0
1989–1993	7	2	3	1	1	0	6	2	1	2	0	0
1994–1998	6	3	3	2	3	23	11	3	1	2	2	0
1999–2003	5	3	3	2	1	12	11	5	2	2	1	0
Finland
1964–1968	0	2	0	0	0	*	0	3	0	2	0	0
1969–1973	1	2	1	1	0	*	4	3	1	2	2	0
1974–1978	3	3	1	0	2	0	8	2	1	2	0	0
1979–1983	4	3	2	1	3	0	8	1	1	1	1	0
1984–1988	6	3	3	1	3	0	19	2	3	2	2	0
1989–1993	8	4	2	1	1	0	12	4	2	1	1	0
1994–1998	6	2	3	3	0	0	9	5	3	2	0	0
1999–2003	6	3	3	2	1	0	11	6	3	2	1	0
Iceland
1964–1968	0	0	0	0	0	*	0	0	0	11	0	*
1969–1973	0	0	0	0	0	*	0	0	0	0	0	*
1974–1978	0	0	0	7	0	*	0	0	0	7	0	*
1979–1983	0	0	0	0	0	*	13	13	13	0	0	*
1984–1988	0	0	5	0	0	*	0	0	0	0	0	*
1989–1993	9	9	5	0	0	*	8	8	8	0	0	*
1994–1998	0	0	0	0	0	*	3	3	3	5	0	*
1999–2003	7	7	3	0	0	*	1	1	1	2	0	*
Norway
1964–1968	4	2	1	2	0	*	0	2	3	2	0	*
1969–1973	3	1	2	1	0	0	8	3	1	1	0	0
1974–1978	7	1	1	2	0	0	12	0	1	1	1	0
1979–1983	2	3	2	1	0	60	6	4	2	1	2	0
1984–1988	5	3	3	1	0	0	0	7	3	1	1	0
1989–1993	9	2	2	1	1	0	11	6	3	1	0	0
1994–1998	8	3	2	1	1	0	19	2	4	2	1	16
1999–2003	9	6	3	1	1	0	11	4	4	2	2	4
Sweden
1964–1968	6	2	2	3	3	0	5	4	3	3	1	0
1969–1973	7	4	3	2	3	0	7	4	4	3	1	0
1974–1978	8	4	1	1	1	0	10	4	2	1	1	0
1979–1983	9	4	2	1	2	21	7	3	4	1	0	0
1984–1988	13	5	2	1	1	0	12	5	1	3	1	0
1989–1993	9	2	2	1	1	0	16	6	3	1	0	7
1994–1998	11	5	4	2	1	0	19	6	4	1	1	0
1999–2003	15	6	4	2	1	0	17	5	5	2	1	0

Numbers in italics indicate that two or more cells had to be combined to get sufficient number of patients to calculate survival.

*Too few patients to calculate survival, see ref. [18].

Discussion

The patient survival trends following the diagnoses of cancer of the digestive organs are subject to large variation according to both tumour sites and study population. A general pattern that emerged was a poorer survival among Danish patients than in the other Nordic countries, in terms of 5-year relative survival as well as excess mortality, with the latter particularly apparent within the first months after diagnosis. Large fluctuations in the Icelandic curves reflect the inherent random variation due to the small Icelandic population size.

Cancers of the oesophagus consist mainly of two subgroups of tumour types, adenocarcinoma and squamous cell carcinoma. The former is mainly associated with obesity, while squamous cell carcinoma is strongly associated with smoking and alcohol consumption [20]. The 2-fold increase in incidence among Danish men stemmed from increase in both types, while in Sweden a decrease in squamous cell carcinoma was accompanied by an equally large increase of adenocarcinoma [21,22]. Apart from being strong risk factors, alcohol and tobacco consumption may also influence the prognosis of patients with respect to their capacity to endure treatment [23]. As in other European countries the Nordic survival of patients with oesophageal cancer is rather poor with no large differences between the countries and only very modest improvements over time.

In contrast to the steady declines in stomach cancer incidence and mortality rates in the Nordic countries in the last 40 years, variations in the extent of more recent increases in 5-year relative survival have led to a 2-fold variability in prognosis at the beginning of the millennium. Stomach cancers are histologically heterogeneous cancers [24] that include two major histologic subtypes, intestinal and diffuse adenocarcinoma. In several European population-based studies [25–27], histological type has been revealed as an independent determinant of stomach cancer survival. The constant declines in incidence and mortality are similar in the Nordic countries and are considered part of the “unplanned triumph” of primary prevention of intestinal-type stomach cancer [28], a near-universal phenomenon possibly mediated through the introduction of refrigerators for preserving food and/or treatment of infection with Helicobacter pylori [10] thus not isolated to the Nordic populations. The variability in the Nordic survival trends and survival estimates, however, largely pertains to disparities in the ability to reduce case fatality among the respective patient populations.

Early diagnosis and treatment appear to be important in stomach cancer survival. However, the excess mortality among Danish patients occurred within the first 12 months of diagnosis, implying that there exists a critical window for early intervention. As observed for other common neoplasms, one might conjecture that Danish patients are on average, diagnosed at a later stage than their Nordic counterparts, leading to a poorer 5-year survival. Consistent with this is a EUROCARE study which suggested that stage at presentation may partially explain survival differences among 17 European populations [29]. One may speculate that other factors such as improving perioperative care (e.g. better surgery and lower perioperative mortality) in combination with chemotherapy and/or radiochemotherapy may also contribute [30,31]. Verdecchia et al. suggested that the modest improvements seen in survival of stomach cancer could be explained by a heterogenous decrease in incidence, with a reduction of only the less aggressive cancers while the incidence of the more aggressive remains stable [32].

The survival among Danish colon, rectum and small intestine cancer patients was inferior to patients in the other Nordic countries. The discrepancy between countries was most notable for cancer of the small intestine which mainly consists of two histologic types, carcinoids and adenocarcinoma, often found in different sub-locations and with different prognosis [12]. A Swedish study showed a 5-year relative survival of nearly 70% in the group with carcinoid tumours, which have had a substantial progress over the past four decades, while it was only around 20% in the adenocarcinoma group [33]. However, the number of cases under study in each country is small and estimates thus uncertain. Based on a comparison between Sweden and Denmark there is no indication that the histological distribution could explain the poorer survival in Denmark (data not shown). Diffuse symptoms result in delayed diagnosis and tumours commonly diagnosed at advanced stages, limiting the possibility of curative treatment. This may thus explain the poorer survival among patients with cancer of small intestine in general [34].

A recent EUROCARE study of colon cancer patients diagnosed 1988 to 1999 showed that the magnitude of survival increases in the Nordic countries was in line with what was observed in other European countries, although improvements in prognosis generally were higher in women than men [32]. The survival among Danish patients has been inferior throughout the study period, and any effects from changes in patient management and care as a result of the changes prior to and after the first Danish Cancer Control plan introduced in year 2000 cannot yet be demonstrated for colon cancer. Patient management as well as the health care system's ability to provide endoscopic investigation has been suggested to influence the survival [35]. During the study period, colon and rectum cancer surgery in Denmark was carried out at many hospitals and only after the end of this study a process of centralisation into fewer units begun [36].

The Nordic trends in incidence and mortality of rectal cancer are in line with those in other European countries [35] and Nordic prognosis is quite good, with the relative survival higher than the European average, with the exception of Denmark [14]. The recently published article by Verdecchia et al. [32] shows that progress in the Nordic countries is smaller among women than men but generally in line with the European average.

Rectal cancer is an example where substantial progress has been achieved within the limitations of existing therapeutic principles via improved local tumour control. The determinants include improvement of surgical technique, total mesorectal excision (TME), preoperative radiation, and a concentration of operations on fewer surgeons with better training [37–40]. Fewer repeat operations after initial surgery are needed in recent years due to the improved skills of surgeons, which in turn results in fewer complications and better prognosis [41]. The sharp decline in excess mortality during the first few months after diagnosis is likely due to this, in combination with more patients receiving an early diagnosis.

Pilot projects of screening for colorectal cancer have taken place in the last decade in several of the Nordic countries, but it is too early to expect influence on the trends in incidence and survival [17]. A high resolution study of rectum adenocarcinoma in the Nordic countries in 1997 with data from Norway, Sweden and Denmark based on the national clinical rectal registers showed that Dukes stage was less favourable in Denmark at diagnosis and that preoperative radiation seldom was used, but that a lower survival still persisted in Denmark when adjusting for stage [42]. As a comparison, approximately 50% of the patients in Sweden now receive preoperative radiotherapy [43], and rectal surgery is concentrated to fewer units throughout the country.

The improvement in patient survival after cancers of the liver, “gallbladder”, or pancreas is very minor in all the Nordic countries, although some advances are noted for liver and “gallbladder” during the last decade. For liver cancer this can probably be explained by improved imaging techniques and early diagnosis in combination with advances in surgical techniques and postoperative care [44] and the reduction in excess mortality during the first month after diagnosis supports this. We found that young patients have a better survival than older patients, although liver cancer is a rare disease before the age of 50. The sudden shifts observed in the liver cancer mortality trends in Denmark and Sweden are likely explained by changes in coding practices (e.g. inclusion of unspecified liver cancers), and autopsy rates particularly in Sweden, not including cases based on death certificates alone.

Survival from cancer in the gallbladder and extrahepatic bile ducts is very poor, although a positive development is that incidence appears to be declining. A study in Scotland showed that declining incidence may be related to an increase in cholecystectomy rate, but no firm conclusions were drawn [45]. There are often no early symptoms of cancer in the gallbladder and extrahepatic bile ducts, and consequently many of them are not diagnosed until the tumour is at an advanced stage, which highly influences outcome. The large variation in survival between European countries in the EUROCARE-4 [14] study most likely relates to small numbers and large variations in tumour stage at diagnosis. Surgery is the primary treatment but this is not always feasible, and as these tumours are not very sensitive to radiation or chemotherapy, cancer care is often palliative. The reduction in excess mortality in the Nordic countries during the first month after diagnosis indicates that life after a gallbladder cancer diagnosis has been prolonged to some extent over the last few decades, but without an early diagnosis, prognosis remains rather poor.

There has been little progress in the prognosis of the pancreatic cancer patients since the 1960s, and this is in line with the lack of significant medical advances in early detection and treatment [35,46]. Incidence and mortality rates of pancreatic cancer generally follow each other closely, although in Sweden the number of deaths from cancer of pancreas (and gallbladder) exceeds the number of incident cases since around 1990. The discrepancy has increased in recent years and is also seen in Denmark. Autopsy rates are low in both countries and this might cause an excess reporting of pancreatic cancer as the underlying cause of death in death certificates [47]. The cancer registry in Sweden does not register cases based on death certificate as the only source.

Pancreatic cancer lacks early symptoms and is, as a consequence, often diagnosed at a late stage when disease has spread to neighbouring tissues, beyond the treatment window of curative resection. The inaccessibility of the pancreas further limits the possibility of surgical removal. The aggressive nature of the tumour leads to a rapid progression that has strong resistance to chemotherapy [46]. Only 10–20% of the cases are operable, which is the only potential cure, and this can be combined with radiotherapy and/or adjuvant chemotherapy. It was reported that such patients experience a better prognosis: about 20% of them survive for five years [2], but a review of long-term survivors from pancreatic cancer in the Finnish cancer registry revealed that most of them were incorrectly diagnosed with a pancreas cancer which indicates that survival actually might be even lower [48]. It has been suggested that the modest improvements in 1-year survival in Norway may reflect more aggressive use of surgery and chemotherapy [49].

Recent randomised trials have not delivered the improved results hoped for; the improvement in survival is small and the additional costs – both in financial terms as well as the risk of toxicity for patients from combination treatment – have been questioned [46]. Meanwhile, the aetiology of pancreatic cancer is not fully understood. Smoking is acknowledged as a risk factor although not all cases are attributable to tobacco. Thus primary prevention aimed at smoking avoidance and cessation, would lead to reduction of incidence but the magnitude of this is unclear. Chua et al. [46] suggested that future research should focus on the biology of the disease at a cellular, molecular and genetic level which might lead to an understanding of both tumour progression and reasons for host resistance to treatment. In addition to this, identifying molecular markers which might be prognostic for outcome could, in the future, help clinicians tailor treatment to each patient. Karim-Kos et al. [35] suggests centralisation of surgery as a possible way to improve survival, which so clearly is demonstrated for rectal cancer [38–40].

Alcohol and tobacco consumption are important risk factors for several cancer sites in the digestive tract and may also have an effect on co-morbidity for these patients. This, as well as other environmental and lifestyle factors, plays a predominant role in the development and prognosis of patients with cancer in the digestive organs, and poses a challenge for future public health in the Nordic countries.

Acknowledgements

The Nordic Cancer Union (NCU) has financially supported the development of the NORDCAN database and program, as well as the survival analyses in this project.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.