PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 10 years since prior chemotherapy No prior nitrosourea based chemotherapy Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 10 years since prior thoracic radiotherapy No more than 3 fractions of prior thoracic radiotherapy for superior vena cava syndrome Prior palliative radiotherapy except to the chest allowed No prior radiotherapy to at least 20% bone marrow No concurrent radiotherapy (including thoracic), except whole brain radiotherapy for CNS progression Surgery: At least 3 weeks since prior major surgery