Long-term results of Phase II study of high dose photon/proton radiotherapy in the management of spine chordomas, chondrosarcomas, and other sarcomas.

Abstract

Negative surgical margins are uncommon for spine sarcomas; hence, adjuvant radiotherapy (RT) may be recommended but tumor dose may be constrained by spinal cord, nerve, and viscera tolerance. Prospective Phase II clinical trial incorporating high dose RT. Eligible patients had primary or locally recurrent thoracic, lumbar, and/or sacral spine/paraspinal chordomas or sarcomas. Treatment included pre- and/or post-operative photon/proton RT ± radical resection. Fifty patients (29 chordoma, 14 chondrosarcoma, 7 other) underwent gross total (n = 25) or subtotal (n = 12) resection or biopsy (n = 13). RT dose was ≤72.0 GyRBE in 25 patients and 76.6-77.4 GyRBE in 25 patients. With 7.3-year median follow-up, the 5 and 8-year actuarial local control (LC) rates were 94% and 85% for primary tumors and 81% and 74% for the entire group. Local recurrence was less common for primary tumors, 4/36 (11%) versus 7/14 (50%) for recurrent tumors, P = 0.002. The 8-year actuarial risk of grade 3-4 late RT morbidity was 13%. No myelopathies were seen. No late neurologic toxicities noted with radiation doses ≤72.0 GyRBE while three sacral neuropathies appeared after doses of 76.6-77.4 GyRBE. LC with this treatment is high in patients with primary tumors. Late morbidity appears to be acceptable.