Background/Objectives
Proton therapy (PRT) has emerged as a treatment option for chordomas/chondrosarcomas to escalate radiation dose more safely. We report results of a phase I/II trial of PRT in patients with chordoma/chondrosarcoma.
Methods
Twenty adult patients with pathologically confirmed, nonmetastatic chordoma or chondrosarcoma were enrolled in a single‐institution prospective trial of PRT from 2010 to 2014. Seventeen patients received adjuvant PRT and three received definitive PRT. Median dose was 73.8 Gy(RBE; range 68.4‐79.2 Gy) using PRT‐only (n = 6) or combination PRT/intensity‐modulated radiotherapy (IMRT) (n = 14). Quality‐of‐life (QOL) and fatigue were assessed weekly and every 3 months posttreatment with the Functional Assessment of Cancer Therapy ‐ Brain (FACTBr) and Brief Fatigue Inventory. Primary endpoint was feasibility (90% completing treatment with < 10 day treatment delay and ≤ 20% unexpected acute grade ≥ 3 toxicity).
Results
Tumors included chordomas of the skull base (n = 10), sacrum (n = 5), and cervical spine (n = 3), and skull base chondrosarcomas (n = 2). Median age was 57. The 80% had positive margins/gross disease. Median follow‐up was 37 months. Feasibility endpoints were met. The 3‐year local control and progression‐free survival was 86% and 81%. There were no deaths. Two patients had acute grade 3 toxicity (both fatigue). One had late grade 3 toxicity (epistaxis and osteoradionecrosis). There were no significant differences in patient reported fatigue or QOL from baseline to the end‐of‐treatment.
Conclusions
We report favorable local control, survival, and toxicity following PRT.