Risk of residual cancer after immediate surgery or nonoperative management after malignant colorectal polypectomy with high-risk features

Guideline recommend colorectal resection when pathology from a malignant colorectal polyp reveals high-risk features (HRF). Some patients opt to avoid surgery. A retrospective cohort study of patients treated between 2015 and 2022 at Memorial Sloan Kettering Cancer Center (New York, NY) compared rates of residual disease between patients who underwent immediate surgery (n=208) and patients managed nonoperatively (n=128) after removal of a malignant polyp with HRFs. Residual disease was identified in 63 patients (19%), either at the time of immediate surgery or during surveillance in the nonoperative group. In the immediate surgery group, 51 (25%) patients had residual disease, including 19 (95) with residual disease in the bowel wall and 39 (19%) in locoregional lymph nodes (LNs). In the nonoperative group, 12 (9%) developed recurrence after polypectomy during surveillance, including 7 (6%) in the bowel wall and 5 (4%) in locoregional LNs. In the nonoperative group, all recurrences were successfully treated with salvage surgery (n=6) or chemoradiotherapy (n=6). Distant metastases occurred in 2% of patients. The authors conclude that the risk of residual disease after removal of a malignant polyp with HRFs approaches 20%. Patients who are concerned about the potential morbidity of surgery should be counseled about this risk, as well as the availability of effective salvage treatments after nonoperative surveillance.