Does short-term androgen deprivation substitute for radiation dose in the treatment of high-risk prostate cancer?

Purpose: Randomized trials have corroborated the clinical benefit of adding androgen deprivation (AD) to radiotherapy (RT) in the treatment of high-risk prostate cancer. Another competing strategy is to escalate the RT dose using three-dimensional conformal RT (3D-CRT). In this analysis, we asked whether the addition of short-term AD (STAD) (less than or equal to6 months) to RT in the treatment of high-risk (prostate-specific antigen >20 ng/mL, Gleason score 8-10, or T3-4) prostate cancer is an effective substitute for dose escalation. Methods and Materials: Between March 1, 1990 and November 30, 1998, 296 high-risk prostate cancer patients were treated with 3D-CRT alone (n = 206) or in combination with STAD (n = 90). The patient characteristics were median age 68 years, median follow-up 58 months, pretreatment initial prostate-specific antigen 21.8 ng/mL, RT dose 75 Gy, STAD duration 3 months, and time off STAD 64 months. The impact of STAD with respect to dose was examined using univariate analysis for dose ranges of <75 Gy and greater than or equal to75 Gy. Stepwise Cox proportional hazards regression multivariate analysis was performed to determine independent correlates of freedom from biochemical failure (bNED), freedom from distant metastasis (FDM), and overall survival. In a separate matched-pair analysis (n = 44 per group), those treated to <75 Gy + STAD (Group A) were compared with those who received greater than or equal to75 Gy alone (Group B). Results: On univariate analysis, the addition of STAD had no impact on bNED, FDM, or overall survival in either dose group. On multivariate analysis, initial prostate-specific antigen level, palpation T stage, and RT dose were significant correlates of bNED. For FDM and overall survival, the significant covariates were palpation T stage and Gleason score, respectively. Finally, in matched-pair analysis, the higher RT dose group had a significantly greater bNED rate at 5 years (Group A 35% vs. Group B 57%, p = 0.0190). Conclusion: Our data suggest that STAD, as used here (median 3 months), is not a substitute for RT dose in the treatment of high-risk prostate cancer. RT dose is an essential element in the treatment of high-risk prostate cancer. (C) 2003 Elsevier Inc.