Between January 1975 and December 1984 1769 polyps were endoscopically removed from 1219 patients. Eight percent of these patients had polyps containing severe atypia and 5.0% had polyps containing invasive cancer. A close postoperative surveillance program was followed by only a few patients, but compliance improved with longer follow-up intervals. Metachronous polyps were observed with similar frequency in patients with benign polyps (34.8%) and those with polyps containing severe atypia (23.8%) or cancer (41.7%). Patients in whom malignant polyps were endoscopically removed had a 5-year survival rate of 84.3% that did not differ from that of patients' whose polyps contained severe atypia (79.0%). It was concluded that endoscopic removal of malignant polyps with favorable histologic conditions does not impair survival. The follow-up program of these patients should be adapted to that of patients with benign polyps, a procedure that may even improve patient compliance.