Dynamics of Androgen Receptor Genomics and Transcriptomics After Neoadjuvant Androgen Ablation

Rationale: Understanding the mechanisms of enzalutamide as an androgen receptor inhibitor in early prostate cancer could lead to improved patient selection for treatment. Objective: To study the effects of enzalutamide on surgical margin status and AR / DNA interaction and gene expression. Study design: A phase II prospective single-arm analysis. With a power of 80% to detect an expected reduction in positive surgical margin rate from 34% to 17% the investigators will have to included 55 men. For the AR/DNA interaction patients will serve as there own control since biopsies will be taken before and after enzalutamide treatment. Study population: Patients over 18 years of age with localized prostate cancer that are planned for prostatectomy. Intervention : Men with localized prostate cancer will undergo an additional set of targeted tumor biopsies and will be subsequently treated with 3 months of enzalutamide. The prostatectomy specimen will be additionally sampled, ex vivo. Main study parameters/endpoints: 1. The effects of neoadjuvant androgen ablation on tumor downstaging. 2. The genetic and transcriptional changes caused by neoadjuvant androgen ablation by enzalutamide. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Burden and risks: Patients will be submitted to an additional set of 4 tumor targeted biopsies under local anesthesia and antibiotic prophylaxis. This comprises a 5 minute intervention with an elevated (2%) risk of postbiopsy urinary tract infection. Additionally oral enzalutamide treatment for a period of 3 months will result in temporary signs of androgen ablation such as: hot flushes (20%), headache (12%), diarrhea (1%), and seizures (0.9%). Benefits: neoadjuvant enzalutamide treatment has been shown to result in tumor and prostate downsizing. Earlier neoadjuvant androgen ablation studies with other agents have shown a reduced positive surgical margin rate and reduced intraoperative blood loss