PRIOR CONCURRENT THERAPY: Biologic therapy: No prior biological therapy or immunotherapy for recurrent or metastatic disease No concurrent biologic therapy Chemotherapy: No prior chemotherapy for recurrent or metastatic disease Prior adjuvant chemotherapy allowed if used as a radiation sensitizer for completely resected disease No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy for recurrent or metastatic disease Prior adjuvant radiotherapy allowed if used as a radiation sensitizer for completely resected disease No radiotherapy to greater than 25% of bone marrow No radiotherapy within the past 4 weeks No concurrent radiotherapy Concurrent CNS radiation allowed Surgery: No post abdominal exploration (with or without resection) within the past 4 weeks Other: No concurrent medication for other medical conditions except for: Analgesics Chronic treatments for preexisting conditions Agents required for life-threatening medical conditions No laxatives