The impact of age on clinical outcomes in men with hormone refractory prostate cancer

Abstract

4622 Background: To determine if men 65 years of age and older have worse clinical outcomes than men younger than 65 years of age with hormone refractory prostate cancer (HRPC). Methods: Data from eight multicenter trials (four phase II and four randomized phase III studies) conducted by the Cancer and Leukemia Group B (CALGB) from 1992–2003 were combined. Eligible patients had progressive adenocarcinoma of the prostate after androgen ablation (with castrate testosterone levels), an ECOG performance status of 0–2, and adequate hematologic, renal and hepatic function. Endpoints were overall survival (OS) and progression-free survival (PFS). Age was analyzed as binary and continuous variables. The log-rank statistic was used to compare OS and PFS between the two groups. In addition, the proportional hazards model was used to assess the prognostic importance of age adjusting for baseline factors in predicting OS and PFS. Results: Of the 1,216 men, 910 (75%) were 65 years or older. Older men were more likely to have had prior radiation (55%) compared to younger men (47%, p=0.01) and had lower alkaline phosphatase levels (median= 153, inter-quartile range (IQR) =95–324) than younger men (median = 172, IQR=105–347, p=0.04). The median survival time was 14.1 months (95% Confidence Interval (CI) = 12.9–15.5) for older men compared to 13.9 months (95% CI=12.63–16.8, p=0.97). The median time to progression was 2.6 months (95% CI=2.4–2.8) compared to 2.4 months (95% CI= 2.1–2.8, p=0.37) for older and younger men, respectively. In multivariate analysis, the hazard ratio (HR) was 2.57 (95% CI= 0.59–11.30, p=0.21) for men 65 years of age and older compared to younger men. Age, on the other hand, was a statistically significant predictor of OS with a HR = 1.07 (95% CI= 1.00–1.1, p=0.023) when analyzed as continuous covariate. Conclusions: There were no statistical significance differences in OS and PFS between older (>=65 years) and younger men (<65 years) with HRPC enrolled on these clinical trials. However, age was a significant predictor of OS when modeled as a continuous variable. It is unknown if these results would hold true in a less selected patient population. No significant financial relationships to disclose.