PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Not specified Life expectancy: More than 2 months Hematopoietic: WBC at least 3,000 Platelets at least 100,000 Hepatic: Bilirubin less than 3 X ULN SGOT less than 3 x ULN Renal: Creatinine less than 1.7 mg/dl (150 micromoles/liter) BUN less than 42 mg/dl (15 mmoles/liter) Other: No requirement for DP or MTX or any medication known to interact with DP, (i.e., antiplatelet or anticoagulant drugs) or MTX (i.e., chemotherapeutic agents) No second malignancy other than basal cell carcinoma of the skin