- Prior external beam radiation therapy (to less than 30% of the bone marrow only) is allowed; at least 28 days must have elapsed since the completion of radiation therapy and the patient must have recovered from side effects; prior treatment with samarium-153 or strontium-86 is allowed if at least eight weeks have elapsed since dosing, and all toxicities have resolved to grade 1; soft tissue disease which has been radiated in the prior 2 months is not assessable as measurable disease