Vertebral metastases reirradiation with volumetric-modulated arc radiotherapy

Purpose: To assess the feasibility, acute toxicity, clinical improvement, local control and survival for spinal metastatic patients re-irradiated using volumetric-modulated-arc-radiotherapy (VMAT). Methods and materials: Between February 2009 and November 2010, 31 patients were treated. Surgery was performed in six before re-irradiation. The clinical target volume (CTV) was defined as the whole vertebrae with recurrence excluding the central section of spinal canal. Planning target volume was defined as CTV + 0-5 mm in the three directions. Dose was prescribed in order to have biological equivalent dose to the spinal cord from the two courses lower than 120 Gy ₂ to 1 cc of the volume. Clinical improvement, toxicity and recurrence were evaluated. All patients had back pain before treatment and 15 (48%) neurological deficit. Results: Clinical remission of pain was obtained in 29 patients (93%). Neurological improvement was observed in 73% of patients. No acute or late toxicities were recorded. No recurrence occurred. Median survival was 10 months (range 6-24). At the last follow-up 19 patients (61%) were alive and 12 (39%) dead from systemic disease progression. The 1 and 2 year survival were 55% and 35%, respectively. Conclusion: In patients with spinal metastases recurrence re-irradiation with VMAT is feasible and provides clinical benefit in most patients.