Authors report long-term efficacy and toxicity outcomes for men treated with stereotactic body radiotherapy (SBRT) for high-risk localized prostate cancer (HRLPC).
Individual patient data from ten prospective clinical studies evaluating SBRT for HRLPC across nine institutions were pooled in the Stereotactic Body Radiotherapy for High-Risk Localized Carcinoma of the Prostate consortium. The Kaplan-Meier method was used to estimate 5-year biochemical recurrence (BCR) and distant metastasis (DM), stratified by receipt of intensified treatment. The impact of intensified treatment on BCR-free survival and DM-free survival was evaluated using multivariable Cox proportional hazards models. Late Common Terminology Criteria for Adverse Events grade ≥2 gastrointestinal (GI) and genitourinary (GU) toxicity was analyzed using time-to-event models.

Findings: In 440 patients with a median follow-up time of 60.4 mo, 5-year BCR and DM rates were 22% and 9.2%, respectively. In the 93 patients (21%) who received intensified treatment, 5-year BCR and DM rates were 7.4% and 3.7%, respectively. Receipt of intensified therapy was associated with a significant reduction in both BCR and DM. For the overall cohort, 5-year rates of grade ≥2 GU and GI toxicity were 23% and 10%, respectively. Authors conclude the safety and efficacy profile of SBRT for HRLPC remains favorable at long-term follow-up, and SBRT should be integrated into shared decision-making for treatment of HRLPC.