Sexually transmitted diseases in cancer patients diagnosed under the age of 20 years – a national registry-based cohort study from Finland

Figures & data

Table 1. Basic characteristics of cancer patients and population comparisons, eligible in analyses regarding sexually transmitted diseases (STDs) registered in the National Infectious Disease Register (NIDR).

	Cancer patients (n = 6,218)		Population comparisons (n = 30,704)
Characteristics	n	%	n	%
Sex
Male	3233	52.0	16003	52.1
Female	2985	48.0	14701	47.9
Age at patient’s cancer diagnosis, years
0–4	2036	32.7	10093	32.9
5–9	1070	17.2	5313	17.3
10–14	1202	19.3	5948	19.4
15–19	1910	30.7	9350	30.5
Period of patient’s cancer diagnosis
1971–1979	675	10.9	3188	10.4
1980–1989	1280	20.6	6303	20.5
1990–1999	2084	33.5	10393	33.8
2000–2009	2179	35.0	10820	35.2
Cancer diagnostic groups
Leukemia	1561	25.1	–	–
Lymphoma	983	15.8	–	–
Central nervous system tumors	1282	20.6	–	–
Neuroblastoma and other peripheral cell tumors	261	4.2	–	–
Retinoblastoma	125	2.0	–	–
Renal tumors	287	4.6	–	–
Hepatic tumors	52	0.8	–	–
Malignant bone tumors	237	3.8	–	–
Soft tissue sarcomas	369	5.9	–	–
Germ-cell, trophoblastic and other gonadal neoplasms	339	5.5	–	–
Other malignant epithelial neoplasms	680	10.9	–	–
Other and unspecified malignant neoplasms	42	0.7	–	–
Sexually transmitted diseases
Total	359	5.8	2034	6.6
Chlamydia*	295 (349)	4.7	1824 (2318)	5.9
Other STDs
All	64	1.0	210	0.7
Hepatitis B	12	0.2	18	<0.1
Hepatitis C	41	0.7	147	0.5
Syphilis	≤5	<0.1	10	<0.1
HIV	≤5	<0.1	6	<0.1
Gonorrhea	≤5	<0.1	29	<0.1
	Median (years)	Range (years)	Median (years)	Range (years)
Attained age at end of follow-up, years (median, range)
Analyses of chlamydia	28.0	0.0–63.6	27.6	0.0–63.6
Analyses of other STDs	27.9	0.0–63.3	27.5	0.0–63.6
Follow-up time, years (median, range)
Analyses of chlamydia	17.0	0.0–20.0	16.4	0.0–20.0
Analyses of other STDs	16.7	0.0–20.0	16.2	0.0–20.0
Age at first STD diagnosis
Chlamydia	22.4	16.2–51.2	21.9	13.8–51.1
Other STDs	23.8	8.2–50.9	24.3	0.5–49.5

*Number of unique persons with chlamydia, overall number of chlamydia infections in parentheses.

Table 2. Basic characteristics of cancer patients and population comparisons, eligible in analyses regarding sexually transmitted diseases (STDs) registered in the Care Register for Health Care (CRHC).

	Cancer patients (n = 6,675)		Population comparisons (n = 33,102)
Characteristics	n	%	n	%
Sex
Male	3496	52.4	17388	52.5
Female	3179	47.6	15714	47.5
Age at patient’s cancer diagnosis, years
0–4	2194	32.9	10919	33.0
5–9	1146	17.2	5702	17.2
10–14	1288	19.3	6403	19.3
15–19	2047	30.7	10078	30.4
Period of patient’s cancer diagnosis
1971–1979	710	10.6	3399	10.3
1980–1989	1553	23.3	7731	23.4
1990–1999	2233	33.5	11152	33.7
2000–2009	2179	32.6	10820	32.7
Cancer diagnostic groups
Leukemia	1685	25.2	–	–
Lymphoma	1029	15.4	–	–
Central nervous system tumors	1415	21.2	–	–
Neuroblastoma and other peripheral cell tumors	292	4.4	–	–
Retinoblastoma	127	1.9	–	–
Renal tumors	298	4.5	–	–
Hepatic tumors	59	0.9	–	–
Malignant bone tumors	273	4.1	–	–
Soft tissue sarcomas	406	6.1	–	–
Germ-cell, trophoblastic and other gonadal neoplasms	352	5.3	–	–
Other malignant epithelial neoplasms	695	10.4	–	–
Other and unspecified malignant neoplasms	44	0.7	–	–
Sexually transmitted diseases
Cervical dysplasia	95	3.0 *	359	2.3 *
Condyloma	93	1.4	430	1.3
	Median (years)	Range (years)	Median (years)	Range (years)
Attained age at end of follow-up
Analyses of cervical dysplasia	27.3	0.0–63.6	26.9	0.0–63.6
Analyses of condyloma	26.6	0.0–63.6	26.2	0.0–63.6
Follow-up time
Analyses of cervical dysplasia	16.5	0.0–28.0	16.1	0.0–28.0
Analyses of condyloma	16.1	0.0–28.0	15.5	0.0–28.0
Age at first STD diagnosis
Cervical dysplasia	27.9	15.2–50.2	27.0	15.9–53.3
Condyloma	23.1	12.7–48.7	24.3	3.1–51.8

*Proportion of female study subjects.

Table 3. Numbers and hazards ratios (HR) for first chlamydia infections and HRs for recurrent chlamydia infections with 95 % confidence interval (CI) among cancer patients and population comparisons.

	Cancer patients (n = 6,218)		Population comparisons (n = 30,704)
	n	1000 pyrs	n	1000 pyrs	HR (95% CI)	Overall HR (95% CI)*
Total	295	86.0	1824	414.5	0.77 (0.69–0.86)	0.79 (0.71–0.88)
Sex
Male	97	44.6	719	215.0	0.64 (0.53–0.79)	0.65 (0.54–0.79)
Female	198	41.4	1105	199.5	0.86 (0.74–0.98)	0.88 (0.77–1.00)
Age at patient’s cancer diagnosis, years
0–4	75	28.7	472	139.7	0.75 (0.60–0.94)	0.77 (0.62–0.95)
5–9	55	14.7	344	71.0	0.76 (0.58–0.99)	0.74 (0.57–0.96)
10–14	62	16.7	388	80.5	0.78 (0.61–1.00)	0.81 (0.64–1.03)
15–19	103	25.9	620	123.3	0.79 (0.65–0.96)	0.82 (0.68–0.99)
Period of patient’s cancer diagnosis
1971–1979	13	12.4	65	57.2	0.94 (0.54–1.62)	0.94 (0.54–1.62)
1980–1989	69	23.6	463	113.3	0.71 (0.56–0.89)	0.71 (0.57–0.89)
1990–1999	133	31.8	812	154.7	0.79 (0.67–0.94)	0.80 (0.68–0.94)
2000–2009	80	18.2	484	89.2	0.78 (0.63–0.97)	0.83 (0.67–1.02)
Cancer diagnostic groups
Leukemia	71	20.8	424	101.0	0.79 (0.62–0.99)	0.79 (0.63–1.00)
Lymphoma	55	13.7	342	66.0	0.77 (0.59–1.00)	0.77 (0.59–1.00)
Central Nervous System	38	17.1	394	81.5	0.46 (0.33–0.63)	0.48 (0.35–0.65)
Other	131	34.4	664	166.0	0.96 (0.81–1.14)	0.98 (0.83–1.15)

*Recurrent chlamydia infections pooled into the analysis.

Table 4. Numbers and hazards ratios (HR) with 95 % confidence interval (CI) for cervical dysplasia among female cancer patients and population comparisons.

	Female cancer patients (n = 3,179)		Female population comparisons (n = 15,714)		HR (95% CI)
	n	1000 pyrs	n	1000 pyrs
Total	95	51.2	359	249.2	1.28 (1.02–1.60)
Age at patient’s cancer diagnosis, years
0–4	11	15.9	77	77.8	0.68 (0.36–1.27)
5–9	12	8.8	63	42.9	0.91 (0.49–1.70)
10–14	27	10.2	60	50.0	2.31 (1.46–3.65)
15–19	45	16.3	159	78.5	1.35 (0.97–1.88)
Period of patient’s cancer diagnosis
1971–1979	14	9.5	60	44.2	1.13 (0.63–2.03)
1980–1989	26	16.5	115	80.3	1.09 (0.71–1.66)
1990–1999	43	16.6	145	82.3	1.45 (1.03–2.04)
2000–2009	12	8.6	39	42.4	1.44 (0.75–2.74)
Cancer diagnostic groups
Leukemia	25	12.6	78	61.7	1.58 (1.00–2.48)
Lymphoma	23	6.8	58	33.3	1.95 (1.20–3.16)
Central Nervous System	10	9.5	70	46.1	0.68 (0.35–1.32)
Other	37	22.3	153	108.1	1.16 (0.81–1.66)

Table 5. Numbers and hazards ratios (HR) with 95 % confidence interval (CI) for condyloma diagnoses among cancer patients and population comparisons.

	Cancer patients (n = 6,675)		Population comparisons (n = 33,102)		HR (95% CI)
	n	1000 pyrs	n	1000 pyrs
Total	93	105.6	430	513.3	1.05 (0.84–1.31)
Sex
Male	26	54.2	159	263.9	0.80 (0.53–1.21)
Female	67	51.4	271	249.4	1.20 (0.91–1.56)
Age at patient’s cancer diagnosis, years
0–4	10	35.1	102	171.3	0.47 (0.25–0.91)
5–9	12	18.4	67	89.6	0.85 (0.46–1.57)
10–14	21	20.6	89	99.9	1.17 (0.73–1.88)
15–19	50	31.6	172	152.4	1.41 (1.03–1.93)
Period of patient’s cancer diagnosis
1971–1979	5	18.0	42	83.6	0.56 (0.22–1.42)
1980–1989	18	34.3	137	166.7	0.64 (0.39–1.04)
1990–1999	46	34.8	194	171.6	1.16 (0.84–1.60)
2000–2009	24	18.5	57	91.4	2.02 (1.25–3.26)
Cancer diagnostic groups
Leukemia	26	25.3	93	124.0	1.34 (0.86–2.07)
Lymphoma	28	16.4	84	79.8	1.62 (1.06–2.49)
Central Nervous System	6	21.0	83	102.1	0.35 (0.15–0.80)
Other	33	42.9	170	207.4	0.95 (0.65–1.38)

Data availability statement

The data that support the findings of this study are available from Statistics Finland. Restrictions apply to the availability of these data, which were used under license for this study. Data are available with the permission of Statistics Finland.