Multimodality treatment of osteosarcoma: Radiation in a high-risk cohort

Purpose. Chemotherapy during radiation and/or bone-seeking radioisotope therapy (153-samarium; 1 mCi/kg) during radiation may improve osteosarcoma cancer control. Patients and Methods. We analyzed our preliminary radiation experience in high-risk, metastatic, and/or recurrent patients during a consecutive period of 20 months (May 2005-December 2006). Results. Thirty-nine high-risk osteosarcoma patients had radiotherapy; 119 sites were irradiated. A median four sites were irradiated per patient (range 1-14). The median radiation dose and number of fractions of radiation was 30 Gy in 10 fractions (range 10-70 Gy in 4-35 fractions). Chemotherapy, most commonly ifosfamide or methotrexate, was used in 80% (100/119) radiotherapy courses. Of 38 painful sites, 29 had improvement (76%), 4 had no change (10%), and 5 had more pain (13%). Objective and potentially durable responses were documented using PET-CT and bone scans with persistent and sustained reduction of standard uptake values (SUVs; initial SUV of indication lesion 9.5 became <4 at all subsequent time points) and serial bone scans [improvement in 29/39 (72%); stable 10/39 (25%), worse 1/39 (3%)]. The actuarial 4-year survival from development of metastasis was 39%. Conclusions. Our early results suggest that the use of multimodality therapy including chemotherapy with radiation in unresectable osteosarcoma may be beneficial.