Excess mortality after curative surgery for colorectal cancer changes over time and differs for patients with colon versus rectal cancer

Figures & data

Table I. Exclusion of colorectal cancer patients who did not undergo curative treatment in 1994–1996 and 2001–2003.

	Total	1994–1996 (%)	2001–2003 (%)	Difference in the proportions for the two time periods (95% CI)
Patients considered for inclusion	18 684*	8769 (28.8)	9915 (31.8)
Patients excluded for having synchronous/ metachronous tumour	1486	373 (4.3%)	508 (5.1%)	0.8 (0.18–1.41)
Patients excluded for having distant metastasis or unknown stage	9024	2294 (27.3)	3060 (32.5)	5.2 (3.85–6.55)
Patients excluded for undergoing non-resectional procedures or non-surgical treatment	1595	638 (10.5)	379 (6.0)	4.5 (3.53–5.48)
Patients included in study	11 437	5464 (28.7)	5973 (31.3)

*Patients treated in 1997–2000 (12 474 patients) were not included in the current analysis.

Data are not shown for patients identified only on the basis of death certificate or autopsy.

Table II. Demographic characteristics and nodal status of 11 437 patients surgically treated with curative intent for colon and rectal cancer in Norway.

		Site
	Total n (%)	Colon n (%)	Rectum n (%)	p-value*
Number of patients	11 437 (100)	7849 (70)	3421 (30)	< 0.001
Sex
Males	5554 (51)	3534 (45)	1945 (57)	< 0.001
Females	5883 (49)	4315 (55)	1476 (43)
Age
≤ 75 years	6896 (60)	4492 (57)	2319 (68)	< 0.001
> 75 years	4541 (40)	3357 (43)	1102 (33)
Nodal status
pN0^**	7473 (65)	5240 (67)	2118 (62)	< 0.001
pN+**	3964 (35)	2609 (33)	1303 (38)

*P-value with regard to site of tumour; **pN0 = no lymph node metastases; pN+ = lymph node metastases present.

Figure 1. >Excess hazard ratio with 99% confidence intervals (CI) in the 1994–1996 period compared with the 2001–2003 period for different postoperative time intervals (0–2 months, 2–12 months, 1–2 years, 2–3 years, 3–4 years, and 4–5 years). A ratio, 1 indicates a lower mortality in the 2001–2003 period compared with the 1994–1996 period. A. Colon cancer. B. Rectal cancer.

Table III. Excess hazard at different postoperative time intervals during the five-year follow-up period, reported as per excess deaths per 1000 person years. Excess hazard figures are provided for the 1994–1996 and 2001–2003 periods.

	All patients				Lymph node-positive ≤ 75 y				Lymph node-positive > 75 y
	Colon		Rectum		Colon		Rectum		Colon		Rectum
	1994–96	2001–03	1994–96	2001–03	1994–96	2001–03	1994–96	2001–03	1994–96	2001–03	1994–96	2001–03
0–2 mo	123	143	70	66	64	112	52	49	337	388	291	171
2–12 mo	70	53	61	28	131	63	104	38	224	220	124	132
1–2 y	63	61	72	36	152	100	156	78	185	200	303	102
2–3 y	80	51	79	49	195	104	172	79	131	91	309	119
3–4 y	50	43	66	54	120	85	150	91	109	108	55	78
4–5 y	37	20	42	45	77	32	102	90	72	40	139	18

Figure 2. Excess hazard ratio with 99% confidence intervals (CI) for colon cancer compared to rectal cancer for different postoperative time intervals (0–2 months, 2–12 months, 1–2 years, 2–3 years, 3–4 years, and 4–5 years). A. 1994–1996 period. B. 2001–2003 period.

Figure 3. Excess hazard ratio with 99% confidence interval (CI) in the 1994–1996 period compared with the 2001–2003 period for patients with lymph node-positive disease during different postoperative time intervals (0–2 months, 2–12 months, 1–2 years, 2–3 years, 3–4 years, and 4–5 years) after curative surgery. For rectal cancer patients aged . 75 years, there were too few incidents to generate a CI for the 4–5 year time interval. A. Colon cancer patients ≤ 75 years. B. Colon cancer patients. 75 years. C. Rectal cancer patients ≤ 75 years. D. Rectal cancer patients . 75 years.