Time to colonoscopy, cancer probability, and precursor lesions in the Danish colorectal cancer screening program

Figures & data

Figure 1 Flow of screening participants.

Abbreviations: FIT, Fecal Immunochemical Test; OC, Optical Colonoscopy.

Table 1 Characteristics among screening participants testing FIT-positive followed by OC (N=57,370)

Characteristics	Time-to-examination (%)
Days	≤30	31–60	61–90	>90	Total
Total participants	11,060 (19.3%)	24,244 (42.3%)	10,237 (17.8%)	11,829 (20.6%)	57,370 (100%)
Gender
Women	4,991 (45.1)	11,064 (45.6)	4,404 (43.0)	4,798 (40.6)	25,257 (44.0)
Men	6,069 (54.9)	13,180 (54.4)	5,833 (57.0)	7,031 (59.4)	32,113 (56.0)
Age, years
50–54	1,304 (11.8)	4,056 (16.7)	2,440 (23.8)	2,533 (21.4)	10,333 (18.0)
55–59	1,340 (12.1)	3,170 (13.1)	1,530 (15.0)	1,583 (13.4)	7,623 (13.3)
60–64	1,854 (16.8)	4,203 (17.3)	1,713 (16.7)	1,859 (15.7)	9,629 (16.8)
65–69	2,639 (23.9)	5,208 (21.5)	1,946 (19.0)	2,421 (20.5)	12,214 (21.3)
≥70	3,923 (35.5)	7,607 (31.4)	2,608 (25.5)	3,433 (29.0)	17,571 (30.6)
Median (IQR)	63.7 (49–76)	63.7 (49–76)	63.7 (49–76)	63.7 (49–76)	63.7 (49–76)
Year of FIT-test
2014	2,346 (21.2)	6,859 (28.3)	2,761 (27.0)	3,632 (30.7)	15,598 (27.2)
2015	3,905 (35.3)	8,466 (34.9)	3,563 (34.8)	4,077 (34.5)	20,011 (34.9)
2016	4,809 (43.5)	8,919 (36.8)	3,913 (38.2)	4,120 (34.8)	21,761 (37.9)

Abbreviations: IQR, interquartile range; FIT, Fecal Immunochemical Test; OC, Optical Colonoscopy.

Table 2 Odds ratios of OC-outcomes as time to conclusive examination increases in screening participants

Time to examination	No. of cases (%)	Adjusted odds ratio (95% CI)^a	Unadjusted odds ratio (95% CI)
Colorectal cancer (n=3,639)
≤30 days	458 (4.1)	1 (reference)	1 (reference)
31–60 days	1,178 (4.9)	1.24 (1.11–1.39)	1.18 (1.06–1.32)
61–90 days	578 (5.7)	1.59 (1.40–1.80)	1.39 (1.22–1.57)
>90 days	1,425 (12.1)	3.49 (3.13–3.89)	3.17 (2.84–3.53)
Advanced stage colorectal cancer (n=1,042)
≤30 days	158 (1.4)	1 (reference)	1 (reference)
31–60 days	380 (1.6)	1.14 (0.95–1.38)	1.10 (0.91–1.32)
61–90 days	178 (1.7)	1.37 (1.10–1.71)	1.22 (0.98–1.51)
>90 days	326 (2.8)	2.10 (1.73–2.56)	1.96 (1.61–2.37)
High-risk adenomas (n=17,732)
≤30 days	3,161 (28.6)	1 (reference)	1 (reference)
31–60 days	6,985 (28.8)	1.01 (0.99–1.10)	1.01 (0.96–1.06)
61–90 days	3,105 (30.3)	1.16 (1.09–1.23)	1.09 (1.03–1.15)
>90 days	4,472 (37.8)	1.59 (1.50–1.68)	1.52 (1.44–1.61)
Low-risk adenomas (n=10,605)
≤30 days	2,268 (20.5)	1 (reference)	1 (reference)
31–60 days	4,887 (20.2)	0.97 (0.92–1.03)	0.98 (0.93–1.03)
61–90 days	1,960 (19.1)	0.91 (0.85–0.97)	0.92 (0.86–0.98)
>90 days	1,490 (12.6)	0.55 (0.51–0.59)	0.56 (0.52–0.60)

Note: ^aAdjusted for gender, year and age.

Abbreviation: OC, Optical Colonoscopy.

Table S1 Different stages of colorectal cancer at different response times among screening participants

Time to examination	No. of cases (%)	Adjusted odds ratio (95% CI)	Unadjusted odds ratio (95% CI)
UICC stage I (n=1.027)
≤30 days	109 (1.0)	1 (reference)	1 (reference)
31–60 days	355 (1.5)	1.57 (1.27–1.95)	1.49 (1.20–1.85)
61–90 days	189 (1.8)	2.16 (1.70–2.74)	1.89 (1.49–2.40)
>90 days	374 (3.2)	3.58 (2.89–4.45)	3.28 (2.65–4.10)
UICC stage II (n=821)
≤30 days	127 (0.5)	1 (reference)	1 (reference)
31–60 days	279 (1.2)	1.05 (0.85–1.30)	1.00 (0.81–1.24)
61–90 days	134 (1.3)	1.32 (1.03–1.68)	1.14 (0.89–1.46)
>90 days	281 (2.4)	2.28 (1.84–2.82)	2.09 (1.70–2.59)
UICC stage III (n=783)
≤30 days	111 (1.0)	1 (reference)	1 (reference)
31–60 days	288 (1.2)	1.23 (0.98–1.53)	1.19 (0.95–1.48)
61–90 days	134 (1.3)	1.46 (1.13–1.88)	1.31 (1.02–1.68)
>90 days	250 (2.1)	2.27 (1.81–2.85)	2.13 (1.70–2.67)
UICC stage IV (n=259)
≤30 days	47 (0.4)	1 (reference)	1 (reference)
31–60 days	92 (0.4)	0.94 (0.66–1.34)	0.89 (0.63–1.27)
61–90 days	44 (0.4)	1.17 (0.77–1.76)	1.01 (0.67–1.53)
>90 days	76 (0.6)	1.66 (1.15–2.40)	1.52 (1.05–2.18)

Note: Adjusted for gender, year and age.

Abbreviation: UICC, Union for International Cancer Control.

Table S2 Sensitivity analysis on time and odds of finding cancer on conclusive examination

Time to FIT from invite	Any colorectal cancer		Advanced stage colorectal cancer
	No. of cases (%)	Odds ratio (95% CI)	No. of cases (%)	Odds ratio (95% CI)
≤30 days	2,412 (6.3)	1 (reference)	698 (1.8)	1 (reference)
31–60 days	821 (5.5)	0.99 (0.91–1.07)	231 (1.5)	0.96 (0.82–1.12)
61–90 days	315 (5.8)	1.06 (0.94–1.20)	103 (1.9)	1.19 (0.97–1.47)
>90 days	184 (5.2)	1.05 (0.90–1.23)	51 (1.4)	0.99 (0.74–1.32)
Time to OC from pos. FIT-test
≤30 days	1,868 (4.2)	1 (reference)	635 (1.4)	1 (reference)
31–60 days	579 (10.1)	2.49 (2.56–2.75)	161 (2.8)	1.93 (1.62–2.30)
61–90 days	220 (11.1)	2.68 (2.31–3.10)	57 (2.9)	1.92 (1.46–2.53)
>90 days	972 (20.1)	5.32 (4.89–5.79)	189 (3.9)	2.59 (2.19–3.06)

Note: Adjusted for gender, year, and age.

Abbreviations: FIT, Fecal Immunochemical Test; OC, Optical Colonoscopy.