 - Patients must be 6 weeks beyond treatment with a nitrosourea or mitomycin-C, 4 weeks beyond other chemotherapy or radiotherapy, and must have recovered to grade 1 toxicity for any treatment-limiting toxicity of prior therapy; exception: patients may have received palliative low-dose radiotherapy to the limbs 1-4 weeks before this therapy, provided pelvis, ribs, sternum, scapulae, vertebrae, or skull were not included in the radiotherapy field 