Efficacy and toxicity outcomes of elderly castrate-resistant prostate cancer patients treated with docetaxel-A pooled analysis of 3 randomized studies.

Background: The current study aims to assess the differences in efficacy and toxicity outcomes according to age among metastatic castrate-resistant prostate cancer patients within a pooled cohort of 3 trials.

Methods: This study is a pooled analysis of the control arms of 3 prospective studies (NCT00273338; NCT00988208; NCT00519285) which assessed docetaxel/prednisone among patients with metastatic castrate-resistant prostate cancer. Incidence of toxicities between the 2 age groups (<75 years vs. ≥75 years) was assessed through chi-squared testing. Through Kaplan-Meier survival estimates, overall survival was compared between the 2 age groups (<75 years vs. ≥75 years). Multivariate Cox regression analysis was then conducted to evaluate factors potentially affecting overall survival.

Results: A total of 1,212 patients were <75 years old and 388 patients were ≥75 years old were included in the pooled analysis. Comparing both patient subgroups together, older patients were more likely to have any high-grade adverse event (P < 0.001), any fatal adverse events (P = 0.007), any-grade anemia (P < 0.001), and any-grade neutropenia (P < 0.001). Using Kaplan-Meier survival estimates, there was no difference in overall survival between both age groups (P = 0.084). Multivariable Cox regression analysis was additionally conducted to further assess the impact of age on overall survival. There was no difference in overall survival according to age (hazard ratio for age < 75 years vs. age ≥ 75 years: 0.883; 0.738-1.057; P = 0.176).

Conclusion: Older patients (≥75 years) have apparently similar survival outcomes compared to younger patients (<75 years). On the other hand, older patients have a higher risk of high-grade toxicities and fatal toxicities compared to younger patients.