To assess whether the risk of death is associated with the time to testosterone recovery (TTR) after radiotherapy (RT) and hormonal therapy (HT) for prostate cancer (PCa).

Between 1995 and 2001, 206 men with localized, unfavorable-risk PCa were randomized to receive RT or RT plus 6 months of HT. A multivariate postrandomization Cox regression analysis was used to assess whether the TTR in years was associated with the risk of death after adjusting for the known prognostic factors, age, Adult Comorbidity Evaluation-27 score, and the use of HT for recurrence.

Of the 102 men randomized to receive RT and HT, 57 (56%) had a TTR of >2 years, and none of these men had died of PCa after a median follow-up of 7.6 years. As the TTR increased, the risk of death decreased significantly (adjusted hazard ratio, 0.60; 95% confidence interval, 0.43-0.84; p = .003). A significant interaction was noted between the TTR and the comorbidity score (p = .002). The survival estimates were similar (p = 0.17) across the TTR values in men with moderate to severe comorbidity; however, these estimates increased significantly (p < .001) with decreasing PCa-specific mortality (p = .006) as the TTR increased in men with no or minimal comorbidity.

The results of our study have shown that a longer TTR after RT plus 6 months of HT for unfavorable-risk PCa is associated with a lower risk of death in men with no or minimal comorbidity.