Radiotherapy and Survival in Prostate Cancer Patients: A Population-Based Study

Purpose: To investigate the association of overall and disease-specific survival with the five standard treatment modalities for prostate cancer (CaP): radical prostatectomy (RP), brachytherapy (BT), external beam radiotherapy, androgen deprivation therapy, and no treatment (NT) within 6 months after CaP diagnosis. Methods and Materials: The study population included 10,179 men aged 65 years and older with incident CaP diagnosed between 1999 and 2001. Using the linked Ohio Cancer Incidence Surveillance System, Medicare, and death certificate files, overall and disease-specific survival through 2005 among the five clinically accepted therapies were analyzed. Results: Disease-specific survival rates were 92.3% and 23.9% for patients with localized vs. distant disease at 7 years, respectively. Controlling for age, race, comorbidities, stage, and Gleason score, results from the Cox multiple regression models indicated that the risk of CaP-specific death was significantly reduced in patients receiving RP or BT, compared with NT. For localized disease, compared with NT, in the monotherapy cohort, RP and BT were associated with reduced hazard ratios (HR) of 0.25 and 0.45 (95% confidence intervals 0.13-0.48 and 0.23-0.87, respectively), whereas in the combination therapy cohort, HR were 0.40 (0.17-0.94) and 0.46 (0.27-0.80), respectively. Conclusions: The present population-based study indicates that RP and BT are associated with improved survival outcomes. Further studies are warranted to improve clinical determinates in the selection of appropriate management of CaP and to improve predictive modeling for which patient subsets may benefit most from definitive therapy vs. conservative management and/or observation.