Polypectomy or surgery for malignant colonic polyps: Do we need to change the NCCN guidelines?

Abstract

4031 Background: Colonoscopic screening and appreciation of the adenoma-carcinoma sequence have led to increased detection and removal of colonic polyps. The National Comprehensive Cancer Network (NCCN) considers polypectomy alone to be adequate therapy for low-grade invasive T1 polyps that are limited to the head/stalk region and can be excised with negative margins. We examined the implications of this guideline for the general population. Methods: The National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database (1988–2003) was queried to identify patients with invasive T1 colonic polyps. Patients treated with a polypectomy (PP) were compared with those who received a surgical resection (SR). Results: Of 9,162 patients with invasive T1 colonic polyps, 61.6% (11,812) underwent SR and 38.4% (7,350) underwent PP. The percentage of polyps removed increased from 4.2% (812) in 1988 to 9% (1739) in 2003. Patients undergoing SR vs. PP had larger polyps (median size 1.3 vs. 1.0 cm, p <0.001) and higher grade tumors (8.6% vs. 4.7%, p <0.001). The percentage of node positivity was 7% after SR, or 8.9% if at least 12 nodes were resected. The percentage of node positivity reached a surprising 6% in 1,478 patients who underwent SR for low-grade polyps limited to the head/stalk, and nodal status significantly affected the 3-year disease-specific survival of this subgroup: 83% with nodal metastases vs. 96% without nodal metastases (p < 0.003). Conclusions: Malignant colonic polyps with favorable histological features have a 6% risk of lymph node metastases even when removed with negative margins, bringing into question the NCCN recommendation that PP alone is adequate therapy. No significant financial relationships to disclose.