Safety and feasibility of image-guided robotic radiosurgery for patients with limited bone metastases of prostate cancer

Objective: To determine the safety and feasibility after image-guided single fraction robotic stereotactic radiosurgery (SRS) in patients with bone metastases of prostate cancer. Materials and methods: Forty patients with 64 bone metastases of prostate cancer were prospectively enrolled in a single center study and underwent 54 consecutive outpatient single session SRS procedures during a 4-year period. F-18 choline PET/CT in addition to standard CT imaging was done prior to SRS in all patients. Nineteen patients were under anti-androgen therapy, 8 patients had undergone chemotherapy before SRS. Overall survival and freedom from local tumor recurrence was analyzed with the Kaplan-Meier method. Results: Mean follow-up was 14 months (3-48 months). Seventy-five percent of patients had a single bone metastasis. The median tumor volume was 13 cc. The mean prescribed tumor dose was 20.2 Gy (16.5-22 Gy). Eight patients had died at the time point of the data analysis. The actuarial 6-months, 12-months, and 24-months local tumor control rate was 95.5% (95% CI: 83.0-98.8) as measured by MRI and PET CT imaging. The median initial PSA before SRS was 5.4 ng/dl (CI: 1.4-8.2) and dropped to 2.7 ng/dl (CI: 0.14-10) after 3 months. One case of progressive neurological deficits was documented. Conclusions: This first report on single session, image-guided robotic SRS documents a safe, feasible, and patient-friendly treatment option in selected patients with bone metastases of prostate cancer. (c) 2013 Elsevier Inc. All rights reserved.