Does adding local salvage ablation therapy provide survival advantage for patients with locally recurrent prostate cancer following radiotherapy?

Some men who experience prostate cancer recurrence post-radiotherapy may be candidates for local salvage therapy, avoiding and delaying systemic treatments. Our aim was to assess the impact of clinical outcomes of adding salvage local treatment in prostate cancer patients who have failed radiation therapy. Methods: Following radiation biochemical failure, salvage transperineal cryotherapy (sCT, n=186), transrectal high intensity focused ultrasound ablation (sHIFU, n=113) or no salvage treatment (NST, identified from the pan-Canadian Prostate Cancer Risk Stratification [ProCaRS] database [n=982]) were compared with propensity-score matching. Primary endpoints were cancer-specific survival (CSS) and overall survival (OS). Results: Median followup was 11.6, 25.1, and 14.3 years following NST, sCT, and sHIFU, respectively. Two propensity-score matched analyses were performed: 1) 196 NST vs. 98 sCT; and 2) 177 NST vs. 59 sHIFU. In the first comparison, there were 78 deaths and 49 prostate cancer deaths for NST vs. 80 deaths and 24 prostate cancer deaths for sCT. There were significant benefits in CSS (p<0.001) and OS (p<0.001) favoring sCT. In the second comparison, there were 52 deaths (31 from prostate cancer) for NST vs. 18 deaths (nine from prostate cancer) for sHIFU. There were no significant differences in CSS or OS possibility attributed to reduced sample size and shorter followup of sHIFU cohort. Conclusions: In select men with recurrent prostate cancer post-radiation, further local treatment may lead to benefits in CSS. These hypothesis-generating findings should ideally be validated in a prospective clinical trial setting.