Radiation therapy for clinically node-positive prostate adenocarcinoma is correlated with improved overall and prostate cancer-specific survival

Purpose: To evaluate the effect of radiation therapy on prostate cancer-specific and overall survival with node-positive cancer in a retrospective Surveillance, Epidemiology and End RESULTS (SEER) population based study.

Methods and materials: The survival of subjects with cT1-T4,cN1,M0 prostate adenocarcinoma diagnosed between 1988 and 2006 were compared with univariate and multivariate Cox regression analysis.

Results: A total of 1100 subjects, with a median age of 69 years and median follow-up time of 90 months, were identified. The 10-year cancer-specific survival for men who had no definitive therapy was 50.3% and for those who had radiation therapy 62.7%. This was significantly different favoring radiation therapy (hazard ratio [HR] = 0.66, 95% confidence interval [CI] = 0.54 to 0.82, P ≤ .01). On multivariate analysis evaluating age, histologic grade, T stage, year of diagnosis, marital status, SEER registry and radiation therapy, radiation therapy (HR = 0.67, 95% CI = 0.54 to 0.84, P ≤ .01), year of diagnosis (HR = 0.96, 95% CI = 0.93 to 0.99, P = .01), and low and intermediate grade disease were correlated with improved CSS. The number needed to treat to prevent 1 prostate cancer-specific death at 10 years was 8 persons. A cause of death analysis revealed non-prostate cancer deaths were not statistically different in the comparison groups.

Conclusions: Radiation therapy is correlated with a clinically significant reduction in all cause and prostate cancer-specific death.