Similar fecal immunochemical test results in screening and referral colorectal cancer

Table 1 Primary indications for colonoscopy

Indication group	Indication for colonoscopy	n
Symptomatic/suspect	Weight loss	52
	Clinical suspicion of diverticulitis	23
	Clinical suspicion of IBD	40
	Abdominal pain	310
	Anemia	174
	Hematochezia	418
	Altered bowel habits	416
	Clinical or radiological suspicion of CRC	49
	Colonoscopy for polypectomy	57
	Diarrhea	115
	Constipation	71
	Total	1725
Screening/surveillance	Average risk	69
	Familial history of CRC	387
	Lynch syndrome	42
	Polyp surveillance	491
	Post CRC surveillance	157
	Total	1146
Other	Not specified/others	143
Grand total		3014

Primary indications for colonoscopy among 3014 patients included in the referral arm of this study in a comparison of fecal immunochemical test results in screening and referral colorectal cancer (CRC) cases (exclusion criteria used in the referral arm of the study were age < 18 years, hospitalization, colostomy, inflammatory bowel disease (IBD) or total colectomy).

Table 2 Colorectal cancer patient characteristics and potential explanations for positive fecal immunochemical test results in addition to colorectal cancer

	Screening population (n = 28)	Referral population (n = 90)
Male %	64	581
Age (yr, mean ± SD)	65 ± 6.5	69 ± 9.82
Location of CRC (% left sided)	64	62
CRC only (%)	6 (21)	32 (36)
CRC including (%)
Advanced adenomas	16 (57)	14 (16)
Other adenomas	5 (18)	17 (19)
Other polyps	0 (0)	14 (16)
Diverticula	1 (4)	9 (10)
Hemorrhoids	0 (0)	4 (4)

¹χ² test: P = 0.54;

²t test: P = 0.04. The percentages of other abnormalities in addition to colorectal cancer (CRC) in the referral population totaled 65% due to rounding. The total percentage of CRC cases with additional pathology was 64%.

Table 3 Fecal immunochemical test results in patients with colorectal cancer derived from a screening and referral cohort according to tissue tumor stage

	Population	n	mean ± SD	25th %	Median	75th %	P value1
All colorectal cancer cases	Screening	28	613 ± 368	283	662	1000	0.02
	Referral	90	829 ± 302	709	1000	1000
T1	Screening	13	498 ± 382	79	384	871	0.22
	Referral	12	725 ± 374	428	1000	1000
T2	Screening	8	787 ± 303	559	936	1000	0.79
	Referral	22	794 ± 341	550	1000	1000
T3	Screening	6	563 ± 368	269	454	1000	0.13
	Referral	52	870 ± 258	888	1000	1000
T4	Screening	1	NA	NA	NA	NA	NA
	Referral	4	793 ± 415	586	1000	1000

¹t test after logarithmic transformation because of non-normality of fecal immunochemical test results (ng/mL). All results ≥ 1000 ng/mL were classified as 1000 ng/mL. T: Tumor stage; NA: Not available. (i.e., values like mean and median having a single observation are meaningless and a t test cannot be performed because no error term can be estimated for a single observation).