Department of Radiation Oncology, University of California-Davis School of Medicine, Davis, CA.
The purpose of this study was to evaluate the effect on freedom from biochemical failure (bNED) or disease-free survival (DFS) by adding hormone therapy (HT) to dose-escalated radiation therapy (HDRT).
We used 883 analyzable prostate cancer patients who enrolled on Radiation Therapy Oncology Group (RTOG) 94-06, a Phase I/II dose escalation trial, and whose mean planning target volume dose exceeded 73.8 Gy (mean, 78.5 Gy; maximum, 84.3 Gy). We defined biochemical failure according to the Phoenix definition.
A total of 259 men started HT 2 to 3 months before HDRT, but not longer than 6 months, and 66 men with high-risk prostate cancer received HT for a longer duration. At 5 years, the biochemical failure rates after HDRT alone were 12%, 18%, and 29% for low-, intermediate-, and high-risk patients, respectively (p < 0.0001). Cox proportional hazards regression analysis adjusted for covariates revealed that pretreatment PSA level was a significant factor, whereas risk group, Gleason score, T-stage, and age were not. When the patients were stratified by risk groups, the Cox proportion hazards regression model (after adjusting for pretreatment PSA, biopsy Gleason score, and T stage) did not reveal a significant effect on bNED or DFS by adding HT to HDRT.
The addition of HT did not significantly improve bNED survival or DFS in all prostate cancer patients receiving HDRT, but did approach significance in high-risk patient subgroup. The result of this study is hypothesis generating and requires testing in a prospective randomized trial.
Valicenti RK, Bae K, Michalski J, Sandler H, Shipley W, Lin A, Cox J. Are you the author?
Reference: Int J Radiat Oncol Biol Phys. 2011 Apr 1;79(5):1323-9.