Salvage stereotactic body radiation therapy for locally recurrent prostate cancer following primary radiation therapy, are benefits worth toxicity risk?: A systematic review

Salvage stereotactic body radiation therapy (SBRT) for local prostate cancer recurrence following radiation therapy remains controversial. Salvage SBRT may cure disease recurrence however receives criticism as it carries with it risks of severe genitourinary and gastrointestinal toxicity. We performed a systematic review to assess the efficacy and side effects profile of salvage SBRT for locally recurrent prostate cancer to assess the role of salvage SBRT in clinical practice. A systematic review was carried out using Pubmed (MEDLINE) and Scopus databases. Inclusion and exclusion criteria were satisfied, and those studies included were quality assessed using the ROBINS-I checklist. Five studies in total met criteria for inclusion. Median doses for SBRT ranged from 30Gy to 36Gy delivered over 5 to 6 fractions. Recurrence free survival ranged from 40% to 76% at 2 years. Genitourinary toxicity was more prevalent than gastrointestinal toxicities. Grade 2 and 3 genitourinary complication rates ranged from 5 – 22% and 0 to 9% respectively. Gastrointestinal grade 2 complication rates ranged from 0 to 11% and no grade 3 complications were recorded. Lower dose SBRT generally was associated with less gastrointestinal and genitourinary side effects however had inferior recurrence free survival rates. This systematic review serves as one of the first to characterise SBRT as a salvage option for locally recurrent prostate cancer. Further large-scale prospective studies are required to guide whether the benefits outweigh the risk profile.