BACKGROUND: The purpose of the study was to determine whether the extent of prostate radiotherapy (ie, whole-pelvic radiotherapy [WPRT] vs. prostate and seminal vesicle radiotherapy [PSVRT]) is associated with all-cause mortality (ACM) in men treated with or without androgen deprivation therapy (ADT).
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PATIENTS AND METHODS: A multiple-institution cohort of 3709 prostate cancer patients was prospectively assembled from 1991 to 2006. The median age was 72 years and all patients had T1c-T3N0M0 adenocarcinoma of the prostate. Patients were treated with WPRT or PSVRT followed by a brachytherapy boost, with or without neoadjuvant ADT (median duration, 4.2 months). Seventy percent of patients had unfavorable-risk disease (Gleason score ≥ 7; prostate-specific antigen ≥ 10 ng/mL; or stage ≥ T2b). Cox regression was applied to determine whether the radiation treatment volume affected the risk of ACM. The interaction between radiation volume and ADT use was assessed.
RESULTS: After a median follow-up of 3.3 years, 561 deaths were observed. A decreased risk of ACM was noted with the use of WPRT versus PSVRT (adjusted hazard ratio [AHR], 0.58; 95% confidence interval [CI], 0.38-0.89; P = .01), or with ADT use (AHR, 0.71; 95% CI, 0.58-0.90; P = .004). However, a combination of WPRT and ADT did not further improve ACM compared with either WPRT alone or PSVRT with ADT. Moreover, there was a significant interaction between the radiotherapeutic treatment volume and ADT (AHR, 1.61; 95% CI, 1.004-2.58; P = .048).
CONCLUSION: Treatment with WPRT or short-course ADT is associated with a decreased risk of ACM, although a combination of the two does not yield greater benefit. This observation suggests a shared mechanism for this risk reduction, which we hypothesize to be via the treatment of micrometastatic disease within the pelvic lymph nodes.
Braunstein LZ, Chen MH, Dosoretz DE, Salenius SA, Katin MJ, Nanda A, D'Amico AV. Are you the author?
Harvard Radiation Oncology Program, Boston, MA; Department of Statistics, University of Connecticut, Storrs, CT; 21st Century Oncology, Fort Myers, FL; UF Health Cancer Center, Orlando, FL; Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, MA.
Reference: Clin Genitourin Cancer. 2015 May 1. pii: S1558-7673(15)00094-4.