OBJECTIVES: To determine prognostic factors to select high-risk men receiving dose-escalated radiation therapy (RT) who will have favorable outcomes with short-term (ST) or no androgen deprivation therapy (ADT).
METHODS: Medical records of 458 men treated with definitive RT for high-risk, nonmetastatic prostate cancer at 3 academic referral centers from 1988 to 2009 were examined. Median dose was 76.4 Gy. Men received no ADT (n=105), STADT (< 12 mo, n=194), or long-term ADT (LTADT: ≥12 mo, n=160). Univariate and multivariable analysis for freedom from distant metastases (FFDM) and cause-specific survival (CSS) were performed. Median follow-up was 71 months.
RESULTS: Seven-year FFDM was 83% and CSS was 91%. Multivariable analysis demonstrated that prostate-specific antigen (PSA) nadir ≤ 0.2 (HR=0.36; 95% CI, 0.20-0.64) and Gleason score (GS) were associated with FFDM and CSS (all P< 0.05). ADT duration was not associated (P>0.05). Those with PSA nadir ≤ 0.2 ng/mL had improved outcomes. Men with GS 9 disease did poorly despite a PSA nadir ≤ 0.2 ng/mL and had improved CSS with LTADT (95% vs. 71%, P< 0.05).
CONCLUSIONS: Select men with high-risk disease treated with dose-escalated RT may not require LTADT. In men treated with ADT, PSA nadir ≤ 0.2 is an independent prognostic factor associated with FFDM and CSS. Men without GS 9 may have acceptable outcomes with STADT if PSA nadir is ≤ 0.2 ng/mL. Further investigation is necessary to elucidate the role of PSA nadir in determining the optimal length of adjuvant ADT.
Son CH, Hamstra DA, Feng FY, Liauw SL. Are you the author?
Department of Radiation and Cellular Oncology, The University of Chicago Medicine, Chicago, IL; Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI.
Reference: Am J Clin Oncol. 2014 Nov 26. Epub ahead of print.