Evaluation of a fecal immunochemistry test prior to colonoscopy for outpatients with various indications

Figures & data

Figure 1 The total number of colonoscopies, included and excluded cases for a 21-month period.

Notes: The indication “screen” includes all patients without any symptoms. This includes average risk, family history of adenomas or adenocarcinoma of the colorectum, previous finding of adenomas or colorectal cancer on previous colonoscopy as well as seven cases sent for colonoscopy because of positive FIT alone. The indication “symptoms” includes all symptoms including rectal bleeding, iron deficiency (with or without anemia), abdominal pain, change in bowel pattern, diarrhea (but not chronic constipation), or weight loss.
Abbreviation: FIT, fecal immunochemistry test; IBD, inflammatory bowel disease.

Table 1 Demographic features of analyzed patients during the period under review

Category	Total	FIT-not done	FIT-done	FIT negative	FIT positive
Number of patients, N	325	181	144	114	30
Mean age (years) (± SD)	60.9 (±12.1)	60.8 (±11.9)	61.0 (±12.5)	60.1 (±12.1)	64.3 (±13.5)
Male gender	171 (52.6)	95 (52.5)	76 (52.9)	57 (50)	19 (63.3)
Withdrawal time in minutes (± SD)
– Including polyps	6.0 (±4.6)	5.3 (±3.5)	6.9 (±5.6)	7.0 (±5.9)	6.4 (±3.7)
– No polyps removed	4.6 (±2.2)	4.2 (±1.7)	5.0 (±2.6)	5.1 (±2.8)	4.5 (±1.5)
Preparation quality (N=287)
– Excellent	207 (72.1)	121 (68.8)	86 (77.5)	66 (81.5)	20 (66.7)
– Good	66 (23.0)	46 (26.1)	20 (18.0)	12 (14.8)	8 (26.7)
– Fair	14 (4.9)	9 (5.1)	5 (4.5)	3 (3.7)	2 (6.7)
Positive FIT onlya	7	–	7	–	7
Screen (average risk)	120 (36.9)	73 (40.3)	47 (32.6)	41 (36.0)	6 (20.0)
Family historya	44 (13.5)	31 (17.1)	13 (9.0)	13 (11.4)	0
Prior polyp/colorectal cancera	49 (15.1)	20 (11.0)	29 (20.1)	24 (21.1)	5 (16.7)
Any symptomsb	105 (32.3)	57 (31.5)	48 (33.3)	36 (31.6)	12 (40.0)
Abdominal pain	31 (9.5)	16 (8.8)	15 (10.4)	11 (9.7)	4 (13.3)
Rectal bleeding	30 (9.2)	16 (8.8)	14 (9.7)	13 (11.4)	1 (3.3)
Change in bowel pattern	15 (4.6)	8 (4.4)	7 (4.9)	5 (4.4)	2 (6.7)
Weight loss	4 (1.2)	4 (1.2)	0	0	0
Iron deficiency ± anemia	28 (8.6)	15 (8.3)	13 (10.4)	7 (6.1)	6 (20.0)

Notes:

a For the purposes of this study, conventional risk factors were treated as screened patients. This includes seven patients colonoscoped for the presence of positive FIT alone. The main division in indications was presence or absence of symptoms;

b some symptoms overlap in the same patient, including rectal bleeding, iron deficiency, abdominal pain or diarrhea, weight loss, and change in bowel pattern. The percentages are based on available data for the entire group. The percent of the specific symptom is calculated based on the total number of patients. Data presented as n (%) unless otherwise indicated.

Abbreviation: FIT, fecal immunochemistry test.

Table 2 Summary of colonoscopy findings in all patients and in the different groupsa

Category	Total	All patients, N=325			FIT-done patients, N =144
		FIT-not done	FIT-done	p-value	FIT negative	FIT positive	p-value
Number of patients	325	181	144		114	30
Advanced adenomas or invasive adenocarcinoma	20 (6.2)	9 (5.0) 2/9 TVA	11 (7.6)	0.3204	4 (3.5)b 1/4 TVA	7 (23.3) 1/7 TVA	0.0016
Overall adenomas	86 (26.5)	46 (25.4)	40 (27.8)	0.6314	28 (24.5)	12 (40.0)	0.0930
CA or TA HGD	7 (2.2)	5 (2.8)c	2 (1.4)c		0	2 (6.7)c
TA =2 cm or 1 cm	13 (4.0)	4 (2.2)	9 (6.3)		4 (3.5)	5 (16.7)
TA <1cm	66 (20.0)	37 (20.1)	29 (20.1)		24 (21.0)	5 (16.7)
HP	7 (2.2)	7 (3.9)	0		0	0
SSA	4 (0.9)	4 (2.2)	0		0	0

Notes:

a The definition of advanced adenomas is based on Corley et al¹⁴ and that of TA, TVA, HGD, CA is based on Kleihues and Sobin.¹¹ HP and SSA are listed to emphasize that these are not part of the definition of adenoma detection rate reference.¹²

b There were no cases of adenoma with HDG or invasive CA in FIT-negative group.

c There were three invasive adenocarcinomas and two adenomas with HDG in FIT-not done group. Both were invasive CAs in FIT-done (Fit+) group. Data presented as n (%).

Abbreviation: CA, invasive adenocarcinoma; FIT, fecal immunochemistry test; HGD, high-grade dysplasia; HP, hyperplastic polyps; SSA, sessile serrated adenomas (SSA); TA, tubular adenoma; TVA, tubulovillous adenoma.

Table 3 Results from multiple variable analyses

FIT-done patients	Odds ratio for all polyps	Odds ratio for advanced polyps
Fit+	1.8 (0.7–4.4)	7.6 (2.0–29.3)
Fit−	reference	reference
Male	4.3 (1.9–10.1)	9.1 (1.1–76.9)
Female	reference	reference
All patients
Male	2.5 (1.5–4.2)	3.9 (1.3–11.9)
Female	reference	reference

Notes: Statistical significance was achieved with FIT for advanced adenomas and male gender was associated with both advanced and all adenomas. These are marked in bold.

Abbreviation: FIT, fecal immunochemistry test.

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KleihuesPSobinLHWorld Health Organization Classification of TumoursLyonsIARC Press2000103

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