High-Dose-Date Brachytherapy or Robotic Ultrahypofractionation for the Treatment of Prostate Cancer Patients: A Matched Pair Analysis

Abstract

To evaluate efficacy and morbidity of robotic ultrahypofractionation CyberKnife® (RU) compared to high-dose-rate (HDR) brachytherapy alone. Two independent prospective trials were conducted in our cancer center between 2008 and 2015. One hundred ninety patients exceeding 6 months of follow-up were enrolled in this study. For the comparison RU patients were matched with the HDR patients 1:1 (outcome blinded with following criteria: Gleason score, maximum PSA, T stage, D’Amico risk, Age). Wilcoxon rank test was used to assess the differences among the groups. Kaplan-Meier method, log-rank test and Cox regression model were used to analyze the survival. There were no statistically significant differences among the two cohorts except for the age. Median follow-up for HDR was 20 months (6-90 mo) and 18 months (6-46 mo) for RU. HDR was linked with higher mild genitourinary toxicity (p-0.03), while RU was associated with higher gastrointestinal morbidity (p-0.002). There was no difference in the time to achieve nadir PSA. Biochemical relapse-free survival was higher in the HDR cohort with borderline significance (93% vs 92%; p-0.069). There were no differences in the overall survival. HDR alone and RU are safe with similar outcomes, however long term data are needed for better evaluation. Moreover randomized controlled study should be constructed to confirm the results.