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).
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.
Written by:
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.
doi: 10.1016/j.clgc.2015.04.010
PubMed Abstract
PMID: 26003267
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