*ASCENDE-RT: An Analysis of Survial Endpoints for a Randomized Trial Comparing a Low-Dose-Rate Brachytherapy Boost to a Dose-Escalated External Beam Boost for High- And Intermediate-Risk Prostate Cancer

Publication date: Available online 24 November 2016
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): W. James Morris, Scott Tyldesley, Sree Rodda, Ross Halperin, Howard Pai, Michael McKenzie, Graeme Duncan, Gerard Morton, Jeremy Hamm, Nevin Murray
PurposeTo report the primary endpoint of biochemical progression free survival (b-PFS) and secondary survival endpoints for a randomized trial comparing two methods of dose escalation for intermediate- and high-risk prostate cancer.Materials and MethodsThe trial enrolled 398 men, median age 68; 69% (N =276) had high-risk disease. After stratification by risk group, subjects were randomized to either a standard arm with 12 months of androgen deprivation therapy (ADT), pelvic irradiation to 46 Gy followed by a dose-escalated external beam radiation therapy (DE-EBRT) boost to 78 Gy, or an experimental arm that substituted a low-dose-rate prostate brachytherapy (LDR-PB) boost. Two hundred trial subjects were assigned to DE-EBRT boost and 198 to LDR-PB boost. Median follow-up is 6.5 years.ResultsIn an intent-to-treat analysis, men randomized to DE-EBRT were twice as likely to experience biochemical failure (MVA HR: 2.04, p =0.004). The 5-, 7-, and 9-year Kaplan-Meier b-PFS estimates were 89%, 86% and 83% for those randomized to LDR-PB boost versus 84%, 75% and 62% for DE-EBRT boost (log rank p <0.001). The LDR-PB boost benefited both intermediate- and high-risk patients. Since the b-PFS curves for the treatment arms diverge sharply after 4 years, the relative advantage of the LDR-PB should increase with longer follow up.In MVA, the only variables correlated with reduced overall survival (OS) were age (MVA HR: 1.06/year, p =0.004) and biochemical failure (MVA HR: 6.30, p <0.001). Although biochemical failure was associated with increased mortality and randomization to DE-EBRT doubled the rate of biochemical failure, no significant OS difference was observed between arms (MVA HR 1.13, p =0.62).ConclusionsCompared to 78 Gy EBRT, men randomized to LDR-PB boost were twice as likely to be free of biochemical failure at 6.5 years median follow-up.



http://ift.tt/2fbRs9W