PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since therapy Chemotherapy: At least 4 weeks since therapy Endocrine therapy: Breast cancer: At least disease stabilization achieved following tamoxifen or other hormonal manipulation if such treatment given previously At least 4 weeks since therapy Nonbreast cancer patients may be entered immediately after conventional doses of megestrol or other hormones Radiotherapy: At least 4 weeks since therapy Concomitant radiotherapy to nonindicator lesions allowed Surgery: At least 4 weeks since therapy