Impact of carbon ion radiotherapy for primary spinal sarcoma.

Background: Spinal sarcomas have been one of the most challenging diseases for orthopedic surgeons. The objective of this study was to retrospectively analyze carbon ion radiotherapy (CIRT) treatment results for spinal sarcoma.

Methods: Forty-seven patients with 48 medically unresectable spinal sarcomas, excluding sacral tumors, received treatment with CIRT between 1996 and 2011. All patients were enrolled in phase 1/2 and phase 2 clinical trials of CIRT for bone and soft tissue sarcoma. The applied dose ranged from 52.8 gray equivalents (GyE) to 70.4 GyE (median, 64.0 GyE) in 16 fixed fractions over 4 weeks.

Results: The median patient age was 54 years, and the cohort included 24 men and 23 women. Thirty-five patients were without prior treatment, and 12 patients had locally recurrent tumors after previous resection. The median follow-up was 25 months, and the median survival was 44 months (range, 5.2-148 months). The 5-year local control, overall survival, and progression free rates were 79%, 52%, and 48%, respectively. None of the 15 patients who had tumors measuring <100 cm(3) had a local recurrence. No fatal toxicities occurred during follow-up. One patient each had a grade 3 late skin reaction and a grade 4 late skin reaction. Vertebral body compression was observed in 7 patients. One patient had a grade 3 late spinal cord reaction. Twenty-two of the surviving 28 patients who had primary tumors remained ambulatory without supportive devices.

Conclusions: CIRT appears to be both effective and safe for the treatment of patients with unresectable spinal sarcoma.