Colon adenoma features and their impact on risk of future advanced adenomas and colorectal cancer

Table 1 Articles summarizing the risk of neoplasia based on the histology of polyps seen at baseline colonoscopy

Ref.	Sample size	Median follow-up, yr	Predictor	Primary outcome	Absolute risk of outcome (%)	RR1 [95%CI]
RCT
Laiyemo et al[11]	1905	4	Villous	ACN	9 (7-11) vs 5 (4-6)	2.3 [1.5-3.4]
Bonithon-Kopp et al[9]	552	3	HGD	ACN	9.8 vs 5.5	1.9 [1.0-3.6]
			Villous		10.3 vs. 6.8	1.7 [0.8-3.7]
Pooled analysis
Martínez et al[14]	8 studies	3.9	HGD	ACN	16.0 (13.2-18.7) vs 10.6 (9.8-11.3)	1.1 [0.8-1.4]
	9167		Villous		16.8 (15.1-18.5) vs 9.7 (9.0-10.4)	1.3 [1.1-1.5]
Meta-analysis
Saini et al[10]	5 studies	3	HGD	ACN	4% risk difference (0-8)	1.8 [1.1-3.2]
			Villous		2% risk difference (-1 to 4)	1.3 [1.0-1.7]
Prospective
Bertario et al[15]	1086	10.5	HGD	CRC	2.8 SIR (0.3-10.2) vs 0.52	Not available
			Tubulovillous Villous	Any adenoma	Not available	1.3 [1.0-1.6]
						1.8 [1.2-2.6]
2Lieberman et al[12]	1193	5.5	No adenomas	ACN	2.4	Ref
			HGD		17	6.8 [2.6-18.1]
			Villous		16	6.1 [2.5-14.7]
Chung et al[8]	3808	4.5	Villous	ACN	Not available	1.5 [0.7- 3.0]
Registry
Van Heijningen et al[13]	2990	2	HGD	AA	13	1.2 [0.8-1.8]
			Villous		8	2.0 [1.2-3.2]
			HGD	ACN	11	Not available
			Villous		17

¹Relative risk compared to patients adenomas without the predictor characteristics. Adenomas with villous compared to those without adenomas with villous features (as opposed to those without any adenomas).

²Relative risk compared to those with no neoplasia. ACN: Advanced colonic neoplasia (includes advanced adenomas and colorectal cancer); AA: Advanced adenomas; CRC: Colorectal cancer; HGD: High grade dysplasia; RCT: Randomized control trial.

Table 2 Articles summarizing the risk of future colonic neoplasia based on the size of polyps seen at baseline colonoscopy

Ref.	Sample size	Median follow-up, yr	Predictor	Primary outcome	Absolute risk of outcome (%)	RR [95%CI]
RCT
Laiyemo et al[11]	1905	4	≥ 10 mm	ACN	9 (7-11) vs 5 (4-6)	0.9 [0.6-1.4]
Bonithon-Kopp et al[9]	552	3	≥ 10 mm	ACN	7.1 vs 7.8	1.1 [0.5-2.1]
Pooled analysis
Martínez et al[14]	8 studies	3.9	< 5 mm	ACN	8.7 (7.7-9.7)	Ref
	9167		10-19 mm		15.9 (14.5-17.4)	2.3 [1.8-2.8]
			≥ 20 mm		19.3 (16.4-22.3)	3.0 [2.2-4.0]
Meta-analysis
Saini I et al[10]	5 studies	3	≥ 10 mm	ACN	2% risk difference (-2 to 6)	1.4 [0.9-2.3]
Prospective
Bertario et al[15]	1086	10.5	≥ 20 mm	Any adenoma	Not available	1.5 [1.1-2.1]
				CRC	SIR	Not available
			Baseline		0.52 [0.3-0.9]
			< 10 mm		0.33 [0.1-0.9]
			≥ 10 mm		0.82 [0.3-1.8]
Lieberman et al[12]	1193	5.5	≥ 10 mm	ACN	15.5 vs 2.4	6.4 [2.7-14.9]
Chung et al[8]	3808	4.5	≥ 10 mm	ACN	Not available	3.0 [1.8-5.1]
Registry
Van Heijningen et al[13]	2990	2	≥ 10 mm	AA	8 vs 4	1.7 [1.2-2.3]

ACN: Advanced colonic neoplasia (includes advanced adenomas and colorectal cancer); AA: Advanced adenomas; CRC: Colorectal cancer; RCT: Randomized control trial; SIR: Standard incidence ratio.

Table 3 Articles summarizing the risk of colonic neoplasia based on the number of polyps seen at baseline colonoscopy

Ref.	Sample size	Median follow-up, yr	Predictor	Primary outcome	Absolute risk of outcome (%)	RR [95%CI]
RCT
Laiyemo et al[11]	1905	4	≥ 3 adenomas	ACN	10 (7-14) vs 6 (5-7)	1.5 [1.0-2.2]
Bonithon-Kopp et al[9]	552	3	≥ 3 adenomas	ACN	18.1 vs 5.0	2.7 [1.2-6.4]
Meta-analysis
Saini I et al[10]	5 studies	3	≥ 3 adenomas	ACN	5% risk difference (1-10)	2.5 [1.1-6.0]
Prospective
1Lieberman et al[12]	1193	5.5	1-2	ACN	4.6	1.9 [0.8-4.4]
			≥ 3		11.9	5.0 [2.1-12.0]
Chung et al[8]	3808	4.5	≥ 3 adenomas	ACN	Not available	3.1 [1.5-6.6]
Registry
Van Heijningen et al[13]	2990	2	1	AA	4	Ref
			2		7	1.6 [1.1-2.4]
			3		8	2.1 [1.3-3.4]
			4		12	2.0 [0.9-4.6]
			≥ 5		18	3.3 [1.7-6.6]
Ng et al[18]	4989	2		AA	Not available	Adjusted OR
			1			3.6 [2.6-5.0]
			2			7.1 [4.9-10.4]
			3			13.7 [0.9-4]

¹Relative risk compared to those with no neoplasia. ACN: Advanced colonic neoplasia (includes advanced adenomas and colorectal cancer); AA: Advanced adenomas; OR: Odds ratio; RCT: Randomized control trial.

Table 4 Risk of concurrent and future advanced adenomas and colon cancer based on serrated polyps

Ref.	Sample size	Median follow-up, yr	Predictor	Primary outcome	Absolute risk	Risk [95%CI]
RCT
Holme et al[20]	100210	10.9	≥ 10 mm serrated polyp	Future CRC	3.4 vs 1.4 cases/1000 patient years	HR 3.3 [1.3-8.6]
Registry
Álvarez et al[17]	5059	None	Proximal l ≥ 10 mm	ACN	Not available	4.2 [1.7-10.2]
			Distal l ≥ 10 mm			2.6 [1.5-4.6]
			Proximal HP			1.6 [1.3-2.3]
Hiraoka et al[16]	10199	None	≥ 10 mm serrated polyps	ACN		4.0 [2.8-5.7]
				CRC	Not available	3.3 [2.2-5.0]
				Proximal CRC		4.8 [2.5-8.4]
Hazewinkel et al[19]	1426	None	Proximal SP	ACN	Not available	2.4 [1.6-3.8]
			Proximal HP			2.0 [1.1-3.4]
			Prox SSA/P			3.0 [1.5-6.2]
			≥ 10 SP			4.0 [1.9-8.6]
			≥ 10 mm HP			3.2 [1.1-9.1]
			≥ 10 mm SSA/P			5.0 [1.7-14.9]
Ng et al[18]	4989	None	SSA	ACN	Not available	4.5 [2.4-8.5]
			Proximal SP			2.2 [1.4-3.6]
			≥ 10 mmSP			59.3 [18.9-186.2]
			≥ 3 SP			4.9 [1.2-19.2]
			≥ 3 non-advanced adenomas			3.6 [2.6-5.0]
Schreiner et al[21]	3121	None	Proximal SP	AA	17.3 vs 10.0	1.9 [1.3-2.7]
			≥ 1 cm SP		27.3 vs 10.3	3.4 [1.7-6.7]
	1371	5.5	Proximal SP	Future
			without adenomas	AA	5.1 vs 2.7	3.1 [1.6-6.2]
			Proximal SP		7.9 vs 6.3	1.2 [0.5-3.8]
			with nonadvanced adenoma		28.9 vs 14.7	2.3 [1.0-5.0]
			Proximal SP
			with advanced adenoma

AA: Advanced adenomas; ACN: Advanced colonic neoplasia (includes advanced adenomas and cancer); HP: Hyperplastic polyp; HR: Hazard ratio; RCT: Randomized control trial; SP: Serrated polyp; SSA: Sessile serrated adenoma.

Table 5 Current guideline recommendations for surveillance based on from United States Multi-society Task Force on colorectal cancer, British Society of Gastroenterology, and European Society of Gastrointestinal Endoscopy[5,27,28]

Organization and yearof guidelines	Recommendations for surveillance of adenomas
	Baseline finding	Timing of next exam, yr
USMSTF on CRC[5], 2012	1-2 small adenomas	5-10
	Adenoma with villous histology	3
	Adenoma with high grade dysplasia	3
	Adenoma ≥ 10 mm	3
	3-10 adenomas	3
	Serrated polyps:
	< 10 mm no dysplasia	5
	≥ 10 mm	3
	Dysplasia	3
	Traditional serrated adenoma	3
British Society of Gastroenterology[28], 2010	1-2 small adenomas	5-10
	3-4 small adenomas	3
	Adenoma ≥ 10 mm	3
	≥ 5 small adenomas	1
	≥ 3 at least one ≥ 10 mm	1
European Society of Gastrointestinal Endoscopy[27], 2010	High risk adenomas:	3
	Adenoma ≥ 10 mm
	Adenomas with high grade dysplasia
	Villous component
	≥ 3 adenomas
	Serrated polyp ≥ 10 mm
	Serrated polyps with dysplasia
	Not high risk adenomas	10

CRC: Colorectal cancer; USMSTF: United States Multi-society Task Force.