Systemic irradiation for selected stage IV and recurrent pediatric solid tumors: Method, toxicity, and preliminary results

Eight patients with advanced pediatric solid tumors received either sequential upper and lower half-body irradiation (HBI) (7.5 rad/min to 500 rad total) or total body irradiation (TBI) (7.5 rad/min to 800 rad total) as part of two multimodality treatment regimens. All patients received combination chemotherapy; drugs were determined by the tumor type. The TBI regimen was selected for two patients who had progression of disease with conventional chemotherapy and for two patients with stage IV neuroblastoma. This intensive regimen consisted of bone marrow harvesting, followed by local radiation to gross disease, marrow-ablative chemotherapy, TBI, and re-infusion of the cryopreserved autologous marrow. Significant acute toxicity was followed by hematologic reconstitution in each patient within seven weeks. At this writing, two patients survive, one of whom is disease free two and one half years without maintenance chemotherapy. A less intensive, outpatient regimen was selected for four patients; three had a complete or good partial response to chemotherapy. The fourth patient had tumor-involved bone marrow not responsive to chemotherapy and was therefore ineligible for marrow cryopreservation and TBI. Each of these four patients received HBI after chemotherapy and local radiation to the primary and/or metastatic sites. Acute toxicity was limited to nausea and vomiting. Significant leukopenia and thrombocytopenia occured in three patients. All four patients were alive 10 to 26 months post HBI. This pilot study demonstrates that chemotherapy can be integrated with local fractionated radiation, and systemic radiation given as HBI or TBI with acceptable toxicity; sufficient bone marrow stem cells can be harvested after conventional chemotherapy and then cryopreserved to permit hematologic reconstitution of the patient who receives marrow ablative therapy.