Impact of Patient Age on Biochemical Recurrence Rates Following Radical Prostatectomy

Abstract

Increased age has been suggested to predict worse clinical outcomes in patients with prostate cancer. An explanation that was proposed for this observation is that it is due to inherent differences in the biological properties of prostate cancer in older men. Stage migration, prostate specific antigen and prostate biopsy pathology are variables that may confound the interpretation of age as an independent prognosticator of outcomes following radical prostatectomy. Matched pairs analysis was performed comparing the 3 age cohorts 46 to 55, 56 to 65 and older than 65 years to a cohort of 435 patients who were 45 years or younger based on propensity scores calculated with all known preoperative variables. Postoperative clinical and pathological characteristics were compared among the 4 matched age cohorts. A Cox hazards model was used to compare time to prostate specific antigen recurrence across the different age cohorts and the actuarial risk of recurrence was calculated using Kaplan-Meier and log rank survivor analyses. Younger patients showed lower grade disease (p <0.001), and lower rates of positive surgical margin rates (p = 0.035) and extraprostatic extension (p <0.001) but they did not have higher rates of lymph node involvement (p = 0.85) or seminal vesicle invasion (p = 0.56). Kaplan-Meier analysis showed no significant differences in biochemical recurrence across the age cohorts (log rank 0.38). On multivariate analysis prostatectomy Gleason score, pathological stage, positive surgical margins (each p <0.001) and preoperative prostate specific antigen (p = 0.04) were independently predictive of biochemical recurrence. We report that increased age is not associated with worse biochemical outcomes following radical prostatectomy and it should not be considered an independent prognosticator for disease recurrence. Rather, age is a surrogate for known predictors of biochemical recurrence following surgery.