Re-irradiation for salvage of prostate cancer failures after primary radiotherapy

Purpose: To review the literature on use of radiation as a salvage option after local-only failure following initial treatment with radiation. Methods: PubMed was searched from inception to June 2012 using terms designed to include relevant articles on salvage radiation as a treatment for local-only failures after radiation. Results: Eighteen separate studies were found which demonstrated widely different patient populations, treatment methods, follow-up periods, and reporting. Only one phase II prospective study was found with no randomized controlled trials. Biochemical disease-free survival (bDFS) at four to 5 years ranged from 20 to 75 %. Patient selection may have influenced these varying rates since some studies with lower bDFS had higher risk populations. Factors associated with improved bDFS included post-treatment prostate-specific antigen (PSA) nadir of <0.5 ng/mL, pre-salvage PSA <6, Gleason score ≤7, and PSA doubling time (PSADT) >10 months. Overall survival ranged from 54 to 94 %, and disease-specific survival ranged from 74 to 100 %. The crude rate of grade 3-4 genitourinary toxicities among all studies was 13 % (range 0-47 %), and the crude rate of grade 3-4 gastrointestinal toxicities was 5 % (range 0-20 %). Incontinence rates were low among reviewed studies at 4 % (range 0-29 %). Conclusions: Brachytherapy represents a reasonable salvage option for patients with local recurrence after initial radiotherapy for prostate cancer. However, rates of toxicities, as in other salvage treatments, can be fairly high, and the likelihood of death from prostate recurrence variable. Prospective studies are needed to better define the efficacy and toxicity of this treatment modality.