Over a 14-year period, 746 patients were treated at the Lille Laser Center for rectosigmoid tumor. Two hundred seventy-two patients were treated for palliation of symptoms from rectosigmoid cancer and 474 patients were treated for a benign rectosigmoid villous adenoma. The immediate success rate and complication rate were 85% and 2%, respectively, for patients with advanced cancer, and 92.8% and 1.8% for those with a villous adenoma. Patients with an advanced cancer remained functionally improved during a 10.1 -month average period after initial improvement. The recurrence rate after initial treatment for villous adenomas was 18% during a 29.7-month average follow-up. Immediate results were influenced by reason for treatment, initial symptoms, and circumferential extension for patients with a cancer, and only by circumferential extension for patients with a villous adenoma. Long-term results were influenced by reason for treatment and circumferential extension for patients with cancer, and by reason for treatment, initial histology and localization for patients with a villous adenoma. Laser treatment provided relief of symptoms in inoperable patients with advanced rectosigmoid carcinomas. Because treatment is long and difficult and the cancer rate is high, endoscopic laser should be limited in patients with a circumferential villous adenoma to nonsurgical candidates. The risk of complication after surgery (some being fatal) has to be balanced against the risk of undetected carcinoma and the indication for endoscopic laser treatment should be discussed case by case.