Cyclic, low-dose total body irradiation for metastatic neuroblastoma.

Total body irradiation (TBI) can be thought of as a systemic anticancer agent. It therefore might best be given like an adjuvant drug, i.e. in tolerable doses, cyclically. The therapeutic ration between normal bone marrow stem cells and suitably sensitive cancer cells should be widened by these means. Fourteen children with advanced (State IV) neuroblastomas were given 100-150 rad TBI in 50 rad daily fractions along with each three-week cycle of standard triple-agent chemotherapy, (vincristine, DTIC, cyclophosphamide). Two patients died of toxicity and one is still undergoing therapy. Four of the remaining 12 survive free of disease for 12+ to 31+ months. The regimen is well tolerated, but prolonged, pronounced bone marrow depression, especially thrombocytopenia, comonly occurs after doses of 300-450 rad.