Stereotactic radiosurgery for patients with spinal metastases from prostate cancer.

Purpose: Spinal metastases may result in intractable pain, neurological deficit, and vertebral body collapse. There are only a few studies describing outcomes following spine stereotactic radiosurgery (SRS) specifically for prostate cancer metastases.

Methods: A prospectively collected database of patients with prostate cancer spinal metastases treated at the University of Pittsburgh Medical Center from 2003 to 2023 was analyzed. The primary outcome was local control (LC). Secondary outcomes were overall survival (OS), pain resolution, and adverse radiation effects (AREs).

Results: Thirty-seven patients and 51 lesions were identified. Fifteen lesions (29%) were previously resected and 34 lesions (67%) were previously irradiated. The median tumor volume was 37.0 cc (range: 2.9-263.3). A majority of lesions (71%) were treated in a single fraction (median 20 Gy, range: 14-22.5); multi-fractionated treatment consisted of 21-30 Gy in 2-5 fractions. Median follow-up was 12 months (range: 1-146). The 6-month, 1-year, and 2-year LC rates were 97%, 91%, and 91%, respectively. No tested prognostic factors were associated with LC, including hormone sensitivity. The 6-month, 1-year, and 2-year OS rates were 71%, 56%, and 32%; age > 70 years (p = 0.048) and tumor volume > 30 cc (p = 0.03) were associated with inferior rates of OS. Complete or partial pain response was observed in 58% of patients. There were 8 instances (16%) of AREs, 2 of which were vertebral compression fractures (4%).

Conclusion: Radiosurgery as a primary or adjuvant treatment modality for prostate cancer spinal metastases confers durable LC and moderate pain relief with minimal toxicity. Further studies are warranted to optimize management in this patient population.