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Adequacy of Colonoscopic Resection of Malignant Polyps
Amy L. Lightner*1, Eric Dozois1, Seth Sweetser2, David W. Larson1, Kellie Mathis1
1Colon and Rectal Surgery, Mayo Clinic, Rochester, MN; 2Gastroenterology, Mayo Clinic, Rochester, MN
Background: Approximately 5% of colonic polyps have a component of invasive adenocarcinoma. There are a number of methods to risk stratify patients harboring adenocarcinoma in endoscopically resected polyps; however, none are conclusive. Given this, we sought to examine1) Incidence of colon adenocarcinoma following polypectomy alone and 2) Incidence of residual carcinoma when a formal oncologic resection was performed following polypectomy, and 3) mortality from colonic neoplasm in either group.
Methods: Following IRB approval, patients who had undergone colonoscopic polypectomy between 2010 and 2014 were identified in the cancer registry database at a tertiary care institution. The major inclusion criterion was the presence of invasive adenocarcinoma in the completely resected polyp. Patients were grouped into operative and non-operative cohorts. Abstracted data included demographics, location and features of polyp, completeness of polyp retrieval, histopathologic features, type of operation performed, surgical histopathology, and disease recurrence.
Results: A total of 76 patients met inclusion criteria. Twenty-five of these patients had invasive adenocarcinoma within the resected polyp and underwent endoscopic surveillance alone (median polyp size 15 mm; range 10 mm-50mm) with a median follow up of 24 months, while 41 patients underwent a formal oncologic surgical resection following polypectomy (median polyp size 20 mm; range 5mm-45mm) with a median follow up of 22 months. Of the 25 patients who had only endoscopic surveillance, 1 patient (4%) had residual disease noted on 6 month colonoscopy and had a T2N0 tumor at surgical resection. Of the 41 patients undergoing segmental colectomy, 2 (5%) had residual adenocarcinoma and 3 (7%) had one or more positive lymph nodes. Four of these five patients had left sided disease. No individual factor (eg size of polyp, location of polyp, pathologic features) was predictive of residual disease at the time of colectomy. There was no mortality in either group related to colonic neoplasm during median follow up of 22 months.
Conclusions: Four percent of patients managed with surveillance alone following endoscopic resection of a malignant polyp had residual disease. Twelve percent of patients managed with formal oncologic resection had mucosal or lymphatic disease in the surgical specimen. No patients in either group experienced mortality related to colonic neoplasm.
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