Impact of age at diagnosis on overall and disease-free survival in men with prostate cancer following conformal 3D radiation therapy.

Aims And Background: The impact of age on prostate cancer outcome has been controversial. The aim of the study was to evaluate the role of age on overall survival and disease-free survival in patients affected by prostate cancer when treated with 3D conformal radiation therapy.

Methods And Study Design: From 1999 to 2005, 1002 patients with T1-T3 prostate cancer were treated with 3D conformal radiation therapy, delivering a median dose of 75.6, 66.6 and 45 Gy to the prostate, seminal vesicles and pelvic nodes (if necessary), respectively. Patients were divided into four groups (<65, 65-70, 70-75, >75 years) according to age at diagnosis. The relationship between age and both overall survival and disease-free survival was calculated with Kaplan-Meier analysis and the comparison between curves was performed by the logrank test. ROC analysis allowed assessment of the best age cutoff.

Results: Mean age was 71 ± 6 years (median, 72). Median and mean follow-up was 71.4 and 69 months, respectively. In multivariate analysis, there was no significant difference in the distribution of disease risk between age groups. Analysis demonstrated that older age is a strong positive predictor of survival (odds ratio for stratified patients older than 70 years was <1). In fact, at the 90 month follow-up, overall survival and disease-free survival varied with age, increasing from 85% to 95% and from 78% to 94%, respectively. ROC curve analysis yielded a cutoff age value discriminating overall survival and disease-free survival of 72 years.

Conclusions: Age is a strong positive predictor of overall survival and disease-free survival, playing a protective role for stratified patients up to 72 years of age.