PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent biologic therapy during first 2 months of study Chemotherapy: No other concurrent local antineoplastic therapy for cutaneous disease No concurrent systemic chemotherapy during first 2 months of study Endocrine therapy: See Disease Characteristics Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy No concurrent radiotherapy during first 2 months of study except for CNS disease Surgery: Not specified