Low serum testosterone levels within the first year of androgen-deprivation therapy (ADT) in men with castration-resistant prostate cancer (PCa) undergoing continuous androgen deprivation (CAD) is associated with improved cause-specific survival, according to a recent study published online ahead of print in the Journal of Clinical Oncology.

Laurence Klotz, MD, of the University of Toronto and fellow researchers conducted a secondary analysis of the PR-7 trial, which randomly assigned patients who had experienced biochemical failure to radiation therapy, radiation plus surgery and CAD, or intermittent ADT.

Using Cox regression, they measured the relationship between testosterone levels in the first year and cause-specific survival as well as time to androgen-independent progression in men who were undergoing CAD.

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They found that patients who consistently had first-year nadir testosterone levels of less than 0.7 nmol/L were significantly more likely to die as a result of disease and the development of hormone resistance.

Maximum testosterone levels of 1.7 nmol/L predicted a higher risk of death as a result of disease.

“Low nadir serum testosterone within the first year of ADT correlates with improved cause-specific survival and duration of response to androgen deprivation in men being treated for biochemical failure undergoing CAD,” the authors concluded.


  1. Klotz, Laurence, et al. “Nadir Testosterone Within First Year of Androgen-Deprivation Therapy (ADT) Predicts for Time to Castration-Resistant Progression: A Secondary Analysis of the PR-7 Trial of Intermittent Versus Continuous ADT.” Journal of Clinical Oncology. doi: 10.1200/JCO.2014.58.297. [epub ahead of print]. March 2, 2015.