Single-Fraction Stereotactic Body Radiotherapy for Oligometastatic Lymph Node Relapse in Prostate Cancer

Background: Stereotactic body radiotherapy (SBRT) emerged as a treatment option in oligometastatic (3 metastases) patients experiencing lymph node relapse from treated prostate cancer. No recommendations are available concerning dose schedule, and available studies report the use of multiple-fraction regimens due to theoretical lower toxicity and higher cumulative dose delivered to the target. The aim of the present study was to evaluate the safety and efficacy of a dose-intensive, single-fraction SBRT regimen. Patients and Methods: Retrospective data on outcome and toxicity from 27 treatments on 23 consecutive patients were collected. Statistical analysis was performed. Results: Median follow-up was 22 months (range 6-63, interquartile range 15-28). Biochemical progression-free survival (bPFS) at 6 months, 1 year, and 2 years were 65%, 40%, and 26%, respectively. In 2 cases acute toxicity of grade 1 were observed. Conclusion: Single-fraction SBRT for lymph node relapse of oligometastatic prostate cancer resulted in promising biochemical control with minimal toxicity.