OUTLINE: This is a randomized study. Patients are stratified according to dominant disease (visceral vs nonvisceral), performance status (0-1 vs 2), and prior chemotherapy in metastatic setting (yes vs no). Patients assigned to arm I receive irinotecan intravenously over 90 minutes every week for 4 weeks followed by a 2 week rest period. Treatment is repeated every 6 weeks in the absence of disease progression or unacceptable toxicity. Patients assigned to arm II receive irinotecan intravenously over 90 minutes every 3 weeks for 6 weeks. Treatment is repeated every 6 weeks in the absence of disease progression or unacceptable toxicity. Quality of life is assessed before and during treatment. Patients are followed every 3 months for 2 years, then annually for 1 year.