Is forceps more useful than visualization for measurement of colon polyp size?

Table 1 Characteristics of colon polyps visualized in the exam

		n (%)
Size	< 5 mm	19 (47.5)
	5 ≥ and < 10 mm	12 (30.0)
	≥ 10 mm	9 (22.5)
Type	Sessile	23 (57.5)
	Semi pedunculated	8 (20.0)
	Pedunculated	5 (12.5)
	LST	4 (10.0)
Location	Rectum	3 (7.5)
	Sigmoid colon	8 (20.0)
	Descending colon	7 (17.5)
	Transverse colon	9 (22.5)
	Ascending colon	11 (27.5)
	Cecum	2 (5.0)
Histology	TA with LGD	27 (67.5)
	TA with HGD	3 (7.5)
	Chronic colitis	6 (15.0)
	Serrated polyp	3 (7.5)
	Inflammatory polyp	1 (2.5)

LST: Lateral spreading tumor; TA: Tubular adenoma; LGD: Low grade dysplasia; HGD: High grade dysplasia.

Table 2 Diagnostic accuracy and error range of the estimation of colon polyp size

	Visual estimation	Forceps estimation	P value
Diagnostic accuracy
Beginners	0.613	0.734	< 0.001
Experts	0.680	0.784	< 0.001
Total	0.639	0.754	< 0.001
Error range (mm)
Beginners	1.68 ± 1.30	1.38 ± 1.08	< 0.001
Experts	1.42 ± 1.11	1.12 ± 1.11	< 0.001
Total	1.48 ± 1.18	1.20 ± 1.10	< 0.001

Table 3 Diagnostic accuracy and error range of the estimation of colon polyp size according to the actual polyp size

	Visual estimation	Forceps estimation	P value
Diagnostic accuracy
≤ 5 mm	0.834	0.929	< 0.001
6-9 mm	0.508	0.692	< 0.001
≥ 10 mm	0.403	0.469	0.018
Error range (mm)
≤ 5 mm	0.90 ± 0.27	0.70 ± 0.17	< 0.001
6-9 mm	1.85 ± 0.82	1.30 ± 0.59	< 0.001
≥ 10 mm	2.71 ± 0.76	2.40 ± 0.67	< 0.001

Table 4 Diagnostic accuracy of the estimation of colon polyp size according to the polyp type

	Visual estimation	Forceps estimation	P value
Sessile type	0.709	0.818	< 0.001
Semi pedunculated type	0.627	0.703	0.344
Pedunculated type	0.608	0.638	0.432
LST type	0.556	0.757	0.012

LST: Lateral spreading tumor.