Does hormone treatment added to radiotherapy improve outcome in locally advanced prostate cancer? Meta-analysis of randomized trials

BACKGROUND: To quantify the magnitude of benefit of the addition of hormone treatment (HT) to exclusive radiotherapy for locally advanced prostate cancer, a literature-based meta-analysis was conducted. METHODS: Event-based relative risks (RR) with 95% confidence intervals (CIs) were derived through a random-effect model. Differences in primary (biochemical failure and clinical progression-free survival) and secondary outcomes (cancer-specific survival, overall survival [OS], recurrence patterns, and toxicity) were explored. Absolute differences and numbers of patients needed to treat (NNT) were calculated. A heterogeneity test, a metaregression analysis with clinical predictors of outcome, and a correlation analysis for surrogate endpoints were also performed. RESULTS: Seven trials (4387 patients) were gathered. Hormone suppression significantly decreased both biochemical failure (RR, 0.76; 95% CI, 0.70-0.82; P < .0001) and clinical progression-free survival (RR, 0.81; 95% CI 0.71-0.93; P=.002), with absolute differences of 10% and 7.7%, respectively, which translates into 10 and 13 NNT. cancer-specific survival (RR, 0.76; 95% CI, 0.69-0.83; P < .0001) and OS (RR, 0.86; 95% CI, 0.80-0.93; P < .0001) were also significantly improved by the addition of HT, without significant heterogeneity, with absolute differences of 5.5% and 4.9%, respectively, which translates into 18 and 20 NNT. Local and distant relapse were significantly decreased by HT, by 36% and 28%, respectively, and no significant differences in toxicity were found. Primary and secondary efficacy outcomes were significantly correlated. CONCLUSIONS: Hormone suppression plus radiotherapy significantly decreases recurrence and mortality of patients with localized prostate cancer, without affecting toxicity.