Colonoscopy surveillance for high risk polyps does not always prevent colorectal cancer

Table 3 Clinical and demographic characteristics of patients who developed post-polypectomy colorectal cancer at site distinct from index AA/TSA/ASSA polypectomy n (%)

Characteristics	Patients with post-polypectomy CRC (n = 54)	Patients who did not develop CRC (n = 162)	P value1
Demographics
Male sex	27 (50.0)	88 (54.3)	0.58
Age ≥ 70	26 (48.2)	52 (32.1)	0.04
Time interval from first treatment for advanced adenoma till cancer or last surveillance colonoscopy in years (median, IQR)	5.11 (2.67-10.37)	6.8 (4.0-10.26)	0.08
Number of colonoscopies between first polypectomy and cancer (mean ± SD)	1.24 ± 1.58	1.65±1.68	0.03
Adenoma size (10-20 mm)	25 (48.1)	106 (65.8)	0.03
Adenoma size (≥ 20 mm)	9 (17.3)	20 (12.4)	0.51
Flat/sessile	47 (92.2)	91 (58.71)	< 0.01
Degree of dysplasia
High grade	17 (31.5)	51(31.5)	-
Low grade/no dysplasia	37 (68.5)	111 (68.5)	-
Number of attempts to remove the polyp (mean ± SD)	1.35 ± 0.68	1.33 ± 0.68	< 0.01
Number of polyps resected at polypectomy (> 3 polyps)	11 (20.4)	15 (9.5%)	0.04
Polypectomy Device used
Hot snare	12 (22.2)	26(16.05)	0.63
Cold snare	4 (7.4)	12(7.0)	0.63
Snare NOS	38 (70.5)	127 (76.5)	0.63
Additional treatments
Piecemeal removal	9 (16.7)	21(13.0)	0.5
Injection-assisted EMR	3 (5.6)	16 (10.0)	0.33
Polyp location
Right colon	31 (57.4)	40 (24.7)	< 0.01
Left colon	13 (24.1)	89 (54.9)	< 0.01
Rectum	10 (18.5)	33 (20.4)	< 0.01

¹P-values for continuous variables were obtained using the Kruskal-Wallis Test; Pearson’s chi-square test was used for discrete variables. CRC: Colorectal cancer.