BACKGROUND: Following polypectomy, colectomy is performed selectively to ensure complete clearance of neoplasia.
OBJECTIVE: This study aimed to determine the risk factors associated with residual disease at colectomy following malignant polypectomy.
DESIGN: This is a retrospective study.
SETTING: This investigation took place at a tertiary teaching cancer center.
PATIENTS: Consecutive patients undergoing polypectomy followed by colectomy from 1990 to 2007 were identified from a prospective database.
MAIN OUTCOME MEASURES: Factors associated with residual disease at colectomy were associated with clinicopathologic features.
RESULTS: Colectomy following polypectomy was performed in 143 patients: 127 with clear invasion of polyp submucosa (invasive disease), and 16 suspicious for submucosal invasion. Residual disease after colectomy was diagnosed in 27 (19%) of 143 patients. Disease was present in the colonic wall in 19 patients (13%): invasive in 16 (11%), and noninvasive in 3 (2.1%). Of the 16 patients with residual invasive disease at colectomy, 15 had clearly invasive disease at polypectomy and 1 was suspicious for invasive disease at polypectomy. Lymph node metastasis was noted in 10 (7.0%) patients. When analyzing patients with clearly invasive disease at polypectomy by margin status, residual invasive disease in the colon wall was noted in 8 of 50 (16%) with <1 mm (positive) polypectomy margin, 7 of 33 (21%) with indeterminate polypectomy margin, and 0 of 44 with ≥1 mm (negative) polypectomy margin (p = 0.009). Nodal metastasis was associated with the presence of lymphovascular invasion (p = 0.01).
LIMITATIONS: This study is limited by its retrospective nature and selection bias.
CONCLUSIONS: Following malignant polypectomy, colectomy should be considered in medically fit patients if the polypectomy margin is positive (≤1 mm) or unknown, or if lymphovascular invasion is present.