The lower the testosterone level achieved in men undergoing androgen deprivation therapy (ADT) for advanced prostate cancer, the better their chances of survival, an Italian study found. Thus, the main goal of ADT should be to lower testosterone to the minimal achievable level, the investigators concluded.
In the study, by Massimo Perachino, MD, and Valerio Cavalli, MD, of Santo Spirito Hospital, Casale Monferrato, patients received 10.8 mg of goserelin (a three-month formulation). Patients were treated during the entire follow-up period. The mean follow-up was 52.3 months, with data available on 162 patients.
Using the medical castration threshold of a testosterone level below 50 ng/mL, 119 patients (73.5%) were considered responders after six months. The researchers found a correlation between testosterone levels at six months and the likelihood of survival.
For example, a patient with Gleason 7 malignancy and a pretreatment PSA level of 50 ng/mL has a 60% five-year probability of survival if the testosterone level at six months is 10 ng/mL, the investigators reported. The five-year probability of survival decreases to 54.3% if the six-month testosterone level is 40 ng/mL.