Association of age and response to androgen-deprivation therapy with or without radiotherapy for prostate cancer: data from CaPSURE.
OBJECTIVE
To assess whether the response to primary androgen-deprivation therapy (PADT) and radiotherapy (RT) plus adjuvant ADT would be muted in older men, as their tumours might already be relatively androgen insensitive, because serum testosterone levels decline with increasing age.


PATIENTS AND METHODS
Using the Cancer of the Prostate Strategic Urologic Research Endeavor database, we conducted an observational study evaluating two groups of men treated for prostate cancer from 1995 to 2006. One group of 1748 men was treated with PADT and the second group of 612 men was treated with RT (external beam RT or brachytherapy) with neoadjuvant and/or adjuvant ADT. We tested whether age was a predictor of disease progression in the PADT group and prostate-specific antigen (PSA) recurrence in the RT + ADT group (Phoenix definition). Secondary outcomes were all cause (ACM) and prostate cancer-specific mortality (PCSM).


RESULTS
In both univariate and multivariate analysis stratifying by clinical risk group, age (<65, 65-69, 70-74, and > or =75 years) was not associated with the risk of secondary treatment or PSA recurrence for the PADT and the RT + ADT groups, respectively. Age category had no relationship to increased ACM or PCSM for the RT + ADT group. However, for the PADT group the oldest category (>75 years) had an increased hazard ratio (2.26, 95% confidence interval 1.04-4.88; P = 0.02) for ACM, but a decreased ratio for PCSM (0.29, 0.21-0.42; P < 0.01).


CONCLUSION
If we assume that age is a valid proxy measure for free available testosterone levels, then these levels do not seem to affect the likelihood of response to ADT, either used alone or combined with RT.