Phase Ii Study Of Enzalutamide Monotherapy With Radiation Therapy For Intermediate Risk Prostate Cancer.

58Background: Castrating androgen deprivation therapy (ADT) is standardly prescribed in combination with radiation therapy (RT) for intermediate or high-risk prostate cancer (PCa). ADT is associated with multiple side effects including weight gain, loss of libido, hot flashes and muscle atrophy. In contrast, enzalutamide monotherapy is associated with much fewer side effects. Methods: At Dana-Farber/ Harvard Cancer Center we performed an open label phase II study of enzalutamide for 6 months as neo- and adjuvant treatment for intermediate risk PCa patients (NCCN criteria) receiving RT. The primary endpoint was the proportion of patients achieving a PSA response of ≤0.2 . This endpoint is predictive of long term PSA response in a similar risk-group of patients treated with RT and ADT. PSA values were obtained at baseline and monthly on 6 cycles of enzalutamide (160mg/day). 79.2 Gy in 44 fractions of IMRT was started between 6 and 10 weeks after the initiation of enzalutamide. Quality of life questionnaires...