Incidence and distribution of advanced colorectal adenomas in patients undergoing colonoscopy for screening, surveillance, and symptoms

Figures & data

Table 1 Demographic and clinicopathological data of the study population

Characteristics	All	Indications for colonoscopy
		Screening	Surveillance	Symptomatic
Subjects	2,810	565	813	1,432
Age, years, mean (SD)	59.8 (11.0)	56.7 (10.5)	59.6 (10.1)	61.2 (11.9)
Men, n (%)	1,533 (54.6)	301 (53.3)	426 (52.4)	806 (56.3)
BMI >25, n (%)	1,358 (48.3)	269 (47.6)	398 (48.9)	692 (48.3)
Family history of colorectal cancer, n (%)	238 (8.5)	46 (8.2)	66 (8.1)	126 (8.8)
Urban areas, n (%)	2,172 (77.3)	436 (77.2)	626 (77.0)	1,110 (77.5)
Colorectal lesions, n	1,285	223	225	837

Abbreviation: BMI, body mass index.

Table 2 Clinicopathological features of colorectal lesions analyzed in the study

Features	Number
All colorectal lesions	1,285
Size, mm, mean (SD)	3–45, 6.7 (1.6)
Morphology
Polypoid	822
Nonpolypoid	463
Location
Proximal colon	474
Distal colon	811
Pathological findings
Intramucosal carcinoma	39
Submucosal carcinoma	9
Adenoma	675
Hyperplastic polyp	546
Othersa	16

Notes:

a There were eight hamartomatous polyps, one ectopic gastric mucosa, three granulation tissue, and four submucosal tumors.

Table 3 Prevalence of ACAs in the subgroups

	Screening subgroup	Surveillance subgroup	Symptomatic subgroup
Patients	565	813	1,432
Total ACA number	34	42	184
Number of patients with ACAs	23	37	157
Prevalence of ACAs (%)	4.1	4.6	11.0

Abbreviation: ACA, advanced colorectal adenoma.

Table 4 Distribution of ACAs and colorectal lesions stratified by anatomic location and morphological appearance into subgroups

Subgroups	Lesion types	Location		Morphology
		Proximal	Distal	Polypoid	Nonpolypoid
Screening subgroup	ACAs	16	18	15	19
	Colorectal lesions	86	137	129	94
Surveillance subgroup	ACAs	22	20	27	15
	Colorectal lesions	95	130	123	102
Symptomatic subgroup	ACAs	53	131	111	73
	Colorectal lesions	300	537	605	232

Abbreviation: ACA, advanced colorectal adenoma.

Table 5 Proportion of ACAs in subgroups stratified by location

Subgroups	Lesion types	Proximal	Distal	Distal vs proximal
				OR	95% CI	P-value
Screening subgroup	ACAs (%)	16 (19.5)	18 (13.1)	0.66	0.37–1.38	0.322
	Colorectal lesions	86	137	–	–	–
Surveillance subgroup	ACAs (%)	22 (23.1)	20 (15.4)	0.60	0.31–1.18	0.139
	Colorectal lesions	95	130	–	–	–
Symptomatic subgroup	ACAs (%)	53 (17.7)	131 (24.4)	1.50	1.05–2.15	0.024
	Colorectal lesions	300	537	–	–	–

Abbreviation: ACA, advanced colorectal adenoma.

Table 6 Proportion of ACAs in subgroups stratified by morphology

Subgroups	Types	Polypoid	Nonpolypoid	Nonpolypoid vs polypoid
				OR	95% CI	P-value
Screening subgroup	ACAs (%)	15 (12.6)	19 (20.2)	1.93	0.92–4.02	0.078
	Colorectal lesions	129	94	–	–	–
Surveillance subgroup	ACAs (%)	27 (22.0)	15 (14.7)	0.61	0.31–1.23	0.165
	Colorectal lesions	123	102	–	–	–
Symptomatic subgroup	ACAs (%)	111 (18.3)	73 (31.5)	2.09	1.48–2.94	<0.001
	Colorectal lesions	605	232	–	–	–