Malignant colon polyps--cure by colonoscopy or colectomy?

Although malignant sessile colon polyps usually require colectomy for proper treatment, the vast majority of malignant pedunculated polyps can be removed colonoscopically for cure. The author's experience with 83 consecutively encountered malignant polypoid lesions is reviewed and is the basis for the discussion herein. All 49 malignant pedunculated polyps were removed colonoscopically. Eight of these patients also underwent colectomy because of questionable or definite presence of cancer cells within the stalk portion of the polyp; no residual cancer was identified at the polypectomy site, and all lymph nodes were negative in these patients. Of 34 patients with malignant sessile polypoid lesions, 13 underwent colectomy because of obvious malignancy at colonoscopy. Twenty-one sessile lesions were removed colonoscopically; with malignancy documented, nine of the 21 patients underwent colectomy. Positive findings (either cancer at the polypectomy site or in lymph nodes) at surgery were identified in two of these nine patients. Colonoscopic polypectomy can be considered curative for malignant pedunculated polyps provided the stalk portion of the lesion is totally uninvolved with the malignant process, provided there is no lymphatic or vascular invasion, the malignancy is well differentiated, and follow-up endoscopic examination of the polypectomy site reveals no residual or recurrence. These four criteria must be satisfied in order to consider a malignant pedunculated polyp curatively removed by colonoscopic polypectomy alone. The risk of colectomy in patients satisfying these four criteria is believed to be greater than the risk of metastatic disease and death from this lesion. Colectomy is recommended for all patients with malignant sessile polypoid lesions, provided their general medical condition provides an acceptable operative risk. Although colonoscopic polypectomy is not recommended for obviously malignant sessile polyps, there are instances where sessile lesions are removed colonoscopically and found microscopically to contain focal or minute areas of invasive cancer. In certain of these patients, the risk of colectomy may exceed the risk of recurrence or metastasis, if the polypoid lesion has been totally removed colonoscopically and completeness of the polypectomy has been documented by follow-up colonoscopy. Each patient's clinical history, general condition, and histopathology must be reviewed individually by a clinician experienced in this field in order to reach a wise and proper decision regarding the potential need for colectomy, and limit colectomy to those patients in whom it is absolutely necessary.