PRIOR CONCURRENT THERAPY: Biologic therapy: Prior interferon only on Protocol CLB-8691 allowed Chemotherapy: Prior oral cyclophosphamide only on Protocol CLB-8691 allowed No concurrent chemotherapy Endocrine therapy: No chronic steroids for other health problems No concurrent steroids for any condition including documented CNS metastases, adrenal failure, or septic shock Nonsteroidal hormonal drugs for nondisease related problems allowed (e.g., insulin for diabetes) Radiotherapy: See Disease Characteristics No prior radiotherapy No concurrent palliative radiotherapy Surgery: At least 2 weeks since prior major surgery Other: No other prior therapy