The Impact of Lesion Morphology and Resection Strategy on Curative Outcomes in Colorectal Malignant Polyps

Colorectal malignant polyps (MPs) appear benign endoscopically but display cancer cell invasion beyond the muscularis mucosae. Their recognition is challenging, as most lack overt signs of submucosal invasion (SMI) despite advances in optical diagnosis. This study aimed to identify the endoscopic features associated with curative resection of MPs.

We conducted a retrospective analysis of patients undergoing colonoscopy at our institution, and those with resected MPs were included.

A total of 165 patients were analyzed, 57.6% males, with a mean age of 65 ± 10 years. A total of 170 MPs were resected with a global curative resection rate of 33.5%. Pedunculated polyps demonstrated a significantly higher curative resection rate (50.8%) compared with nonpedunculated lesions (23.4%; P < .001; OR 3.4, 95% CI, 1.74-6.6). On multivariate analysis, piecemeal resection was independently associated with noncurative outcomes for both pedunculated (P = .027) and nonpedunculated polyps (P = .013). In the latter group, indirect signs of deep SMI were also significantly associated with a noncurative resection (P = .01). Supporting these results, the major causes for a noncurative resection were specimen fragmentation (35.5% in pedunculated, 57% in nonpedunculated polyps) and insufficient margins, defined as a vertical margin < 1 mm or R1 resection (41.9% in pedunculated, 36.7% in nonpedunculated polyps).

Polyp morphology and resection strategy are key determinants of curative outcomes in MPs. En bloc resection should be achieved in lesions suspected of SMI, as piecemeal removal is a leading cause of noncurative outcomes.