SUO 2017: Surgical And Imaging Findings Of Neoadjuvant Enzalutamide And Androgen Deprivation Therapy For High Risk Prostate Cancer: An Initial Case Study For An Ongoing Clinical Trial

Washington, DC ( Introduction: Neoadjuvant androgen deprivation therapy (ADT) for high-risk prostate cancer (PCa) has been shown to decrease the risk of positive surgical margins, but promotes no improvements in biochemical recurrence (BCR) or survival. However, little research has been conducted to evaluate the efficacy of neoadjuvant enzalutamide (NA-enza), a selective androgen receptor blocker, plus ADT on PCa. In this study, the authors evaluated the surgical and imaging results of an ongoing clinical trial of NA-enza and ADT therapy prior to radical prostatectomy (RP).

Methods: The authors report on an ongoing clinical trial (NCT02430480) at a single institution recruiting treatment-naïve patients with intermediate risk (IR) (Gleason score [GS] 7, PSA 10-20, or stage T2b on magnetic resonance imaging [MRI]) or high risk (HR) (GS 8, PSA >20, or stage T3) PCa. Patients with distant metastases detected on imaging were excluded. All patients underwent MRI-transrectal ultrasound (TRUS)-guided fusion biopsy (Fbx), a six-month course of enzalutamide and goserelin, followed by MRI and RP. Evidence of BCR was monitored with PSA measurements.

Results: Up to this time point, 20 enrolled patients completed neoadjuvant treatment, MRIs, and robotically-assisted RP. Mean tumor volume decreased by 80.7% and 9/19 cases down-staged from clinical T3/T4 disease on pre-neoadjuvant MRI to pT2 disease on final pathology. 3 cases demonstrated pathological complete response. Post neoadjuvant MRI correctly staged 15/20 cases and 1 case was upstaged. Mean estimated blood loss was 355 (+/- 205) and a mean of 25 lymph nodes were dissected (17-37). Nerve-sparing was achieved in 15 cases with no complications noted.

Conclusion: mpMRI is an effective measure of treatment response and down-staging confirmed on final pathology after neoadjuvant therapy. Treatment response can be dramatic, but the degree of response varies between lesions from minimal response to complete response.

Speaker: Samuel Alexander Gold

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, @GoldbergHanan, at the 18th Annual Meeting of the Society of Urologic Oncology, November 29-December 1, 2017 – Washington, DC