Advanced age at diagnosis is an independent predictor of time to death from prostate carcinoma for patients undergoing external beam radiation therapy for clinically localized prostate carcinoma

BACKGROUND. Whether age at diagnosis is predictive of time to prostate carcinoma specific death after external beam radiation therapy (RT) for patients who are diagnosed with clinically localized prostate carcinoma during the prostate specific antigen (PSA) era has not been investigated previously. METHODS. A multivariate Cox regression analysis was used to evaluate the ability of pretreatment risk group and age at diagnosis to predict time to all causes of death and time to death from prostate carcinoma for 381 patients who underwent RT for clinically localized prostate carcinoma. RESULTS. Age at diagnosis, as a continuous variable (P-continuous = 0.04) and risk group (P-categorical = 0.02) were independent predictors of time to death from prostate carcinoma, whereas only age at diagnosis (P-cotinuous = 0.01) was a predictor of time to all causes of death. When analyzed as a categorical variable, beginning at age 73 years, age at diagnosis was an independent predictor (P-categorical < 0.04) of time to death from prostate carcinoma. Upon further analysis, this finding was limited to high-risk patients. For example, age >= 75 years at diagnosis predicted for a shorter median time to death from prostate carcinoma (6.3 years vs. 9.7 years; P = 0.002) in high-risk patients. CONCLUSIONS. Patients with clinically localized, high-risk prostate carcinoma who were diagnosed at age >= 73 years and were treated with RT had a worse prognosis compared with patients who were diagnosed age < 73 years, raising the possibility that a more aggressive prostate carcinoma biology may develop during andropause.