A Prospective Study of the Relationship Between Clinical Outcomes After Enzalutamide and Serum Androgen Levels Measured via Liquid Chromatography-tandem Mass Spectrometry in Patients with Castration-resistant Prostate Cancer

Background Enzalutamide (ENZ) is used to treat patients with castration-resistant prostate cancer (CRPC). However, the kinetics of serum androgens before and after ENZ treatment are unknown. Objective To elucidate the kinetics of serum androgens and explore the possibility of identifying a useful marker for predicting the effects of ENZ. Design, setting, and participants We conducted a prospective study from 2014 to 2018 at Gunma University Hospital and related facilities. Data were analyzed for 104 patients with CRPC treated with ENZ. Outcome measurements and statistical analysis We measured serum androgen levels using liquid chromatography-tandem mass spectrometry. Relationships with outcomes were assessed using multivariable Cox regression and log-rank analyses. Results and limitations The median age of the patients was 73 yr. Median serum testosterone, dihydrotestosterone (DHT), androstenedione, and dehydroepiandrosterone sulfate levels were 49.0, 5.8, 222.2, and 326.3 pg/ml, respectively. We performed multivariate analysis using Cox regression to predict prostate-specific antigen progression–free survival (PSA-PFS) and overall survival (OS). Hemoglobin level (≥12.5 vs
Take Home Message The effect of enzalutamide was significantly better for cases with high blood androgen levels before treatment. In addition, the incidence of adverse events of anorexia, malaise, and fatigue tended to be low. These results suggest that serum androgen levels before enzalutamide treatment may be useful for predicting efficacy, prognosis, and the incidence of adverse events.