Patient management after endoscopic removal of the cancerous colon adenoma.

The subject of management of patients after endoscopic removal of cancerous adenomas is controversial. A retrospective review of 126 lesions in 121 patients who had had colonoscopic polypectomy of malignant lesions between 1971 and 1985 was used to determine the criteria for colon resection. Invasive cancer was identified in 80 patients, while 41 patients had carcinoma in situ. A synchronous colon cancer was found in five of the 121 patients. The patients who had carcinoma in situ had no evidence of residual tumor or metastatic disease on subsequent follow-up (colon resection in three patients and endoscopic surveillance in 38 patients). Of the 80 patients with invasive cancer, 44 had subsequent colon resection, and 34 of these had no evidence of tumor in the resected bowel or mesenteric lymph nodes. Ten patients had residual tumor, metastatic cancer to regional lymph nodes, or both. Each of the 10 had at least one of the following indications of inadequate resection or dissemination of disease to local lymph nodes (the first indication is a macroscopic evaluation, while the remaining four are all microscopic): incomplete excision, poorly differentiated tumor, invasion of the line of resection, invasion of the polyp stalk, and invasion of venous or lymphatic channels. Present recommendations for patient management after endoscopic removal of an invasive malignant adenoma should include colon resection with regional lymphadenectomy for patients with one or more of these five criteria. Patients without any of these risk factors should have early repeat endoscopic examination 3 months after initial polypectomy to evaluate the polypectomy site. Total colonoscopic examination is repeated at 1 year to ensure the surveillance program is begun with a colon without neoplasms.