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

Table 1 Clinical and demographic characteristics of patients who developed colorectal cancer at the index AA/TSA/ASSA resection site n (%)

Characteristics	Developed CRC (n = 84)	No CRC (n = 252)	P value1
Demographics
Male sex	56 (66.7)	138 (54.8)	0.06
Age, yr (≥ 70)	40 (47.6)	85 (33.7)	0.02
Time interval from first treatment for advanced adenoma till cancer or last surveillance colonoscopy in years (median, IQR)	4.24 (1.51-7.23)	6.0 (4.05-9.35)	< 0.01
Number of colonoscopies between first polypectomy and cancer (mean ± SD)	1.65 ± 2.30	1.47 ± 1.6	0.83
Adenoma size (1-2 cm)	31 (42.5)	146 (58.2)	0.03
Adenoma size (> 2 cm)	20 (27.4)	27 (10.8)	0.0007
Flat/sessile	76 (91.6)	161 (66.8)	< 0.01
Degree of dysplasia
High grade	28 (33.3)	66 (26.2)	0.18
Low grade/no dysplasia	56 (66.7)	186 (73.8)	0.18
Number of attempts to remove the polyp (mean ± SD)	2.05 ± 1.62	1.26 ± 0.60	< 0.01
Number of polyps resected (> 3 polyps)	14 (16.7)	21 (8.3)	0.03
Polypectomy device used
Hot snare	19 (24.1)	41 (16.3)	0.11
Cold snare	5 (6.3)	26 (10.3)	0.11
Snare NOS	60 (75.9)	185 (73.4)	0.11
Additional treatments
Piecemeal removal	21 (27.6)	30 (13.1)	< 0.01
Mucosal lift	13 (17.1)	23 (10.0)	0.10
Polyp location
Right colon	63 (75.0)	110 (43.7)	< 0.01
Left colon	8 (9.52)	106 (42.1)	< 0.01
Rectum	13 (15.5)	36 (14.3)	< 0.01

¹P-values for continuous variables were obtained using the Kruskal-Wallis Test; Pearson’s χ² test was used for discrete variables. CRC: Colorectal cancer.