Radical prostatectomy versus external beam radiation therapy for high-grade, clinically localized prostate cancer: Emulation of a target clinical trial.

PURPOSE: The comparative effectiveness of surgery and radiation therapy for high-grade, clinically localized prostate cancer remains a seminal, open question in urologic oncology, with no randomized controlled trials to inform management. We therefore emulated a hypothetical target clinical trial of radical prostatectomy (RP) versus external beam radiotherapy (EBRT) for high-grade, clinically localized prostate cancer. MATERIALS AND METHODS: We conducted observational analyses using the National Cancer Database from 2006-2015 to emulate a target clinical trial in men 55-69 years with cT1-3cN0cM0, PSA<20 ng/mL, Gleason 8 to 10 prostate adenocarcinoma treated with RP or 75 to 81 Gy EBRT with androgen deprivation therapy (EBRT+ADT). The associations of treatment type with overall survival (OS) were estimated using Cox regression with stabilized inverse probability weights (IPW). RESULTS: A total of 26,806 men formed the study cohort (RP: 23,990; EBRT+ADT: 2,816). Baseline characteristics were well-balanced after IPW-adjustment. Median follow-up was 48.4 (IQR 25.5-76.2) months. After IPW-reweighting, RP was associated with improved OS compared to EBRT+ADT (HR 0.54;95% CI 0.48-0.62; P<0.001), with 5- and 10-year OS of 93% vs 87%, and 76% vs 60%, respectively. RP was associated with improved OS across all categories of Gleason score, PSA, cT stage, age, and Charlson comorbidity index examined. In sensitivity analyses adjusting for biopsy tumor volume and a biopsy-specific Gleason score, RP remained associated with improved OS compared to EBRT+ADT (HR 0.62;95% CI 0.49-0.78; P<0.001). CONCLUSIONS: In observational analyses designed to emulate a target clinical trial of men with high-grade, clinically localized prostate cancer, RP was associated with improved OS compared with EBRT+ADT.

Results of a Randomized Phase II Trial of Intense Androgen Deprivation Therapy prior to Radical Prostatectomy in Men with High-Risk Localized Prostate Cancer.

PURPOSE: This multicenter randomized phase 2 trial investigates the impact of intense androgen deprivation on radical prostatectomy pathologic response and radiographic and tissue biomarkers in localized prostate cancer (NCT02903368). MATERIALS AND METHODS: Eligible patients had a Gleason score ≥4+3=7, prostate specific antigen >20 ng/mL or T3 disease and lymph nodes <20 mm. In Part 1, patients were randomized 1:1 to apalutamide, abiraterone acetate, prednisone and leuprolide (AAPL) or abiraterone, prednisone, leuprolide (APL) for 6 cycles (1 cycle=28 days) followed by radical prostatectomy. Surgical specimens underwent central review. The primary end point was the rate of pathologic complete response or minimum residual disease (minimum residual disease, tumor ≤5 mm). Secondary end points included prostate specific antigen response, positive margin rate and safety. Magnetic resonance imaging and tissue biomarkers of pathologic outcomes were explored. RESULTS: The study enrolled 118 patients at 4 sites. Median age was 61 years and 94% of patients had high-risk disease. The combined pathologic complete response or minimum residual disease rate was 22% in the AAPL arm and 20% in the APL arm (difference: 1.5%; 1-sided 95% CI -11%, 14%; 1-sided p=0.4). No new safety signals were observed. There was low concordance and correlation between posttherapy magnetic resonance imaging assessed and pathologically assessed tumor volume. PTEN-loss, ERG positivity and presence of intraductal carcinoma were associated with extensive residual tumor. CONCLUSIONS: Intense neoadjuvant hormone therapy in high-risk prostate cancer resulted in favorable pathologic responses (tumor <5 mm) in 21% of patients. Pathologic responses were similar between treatment arms. Part 2 of this study will investigate the impact of adjuvant hormone therapy on biochemical recurrence.

Outcomes of Post-Neoadjuvant Intense Hormone Therapy and Surgery for High Risk Localized Prostate Cancer: Results of a Pooled Analysis of Contemporary Clinical Trials.

PURPOSE: We report on the post-radical prostatectomy outcomes of patients enrolled in 3 randomized, multicenter, clinical trials of intense neoadjuvant androgen deprivation therapy prior radical prostatectomy. MATERIALS AND METHODS: All patients included were enrolled in trials evaluating intense androgen deprivation therapy followed by radical prostatectomy. The primary end point was time to biochemical recurrence, defined as the time from radical prostatectomy to prostate specific antigen >0.1 ng/ml or start of first post-radical prostatectomy therapy, stratified by pathological response at radical prostatectomy (presence or absence of exceptional pathological response defined as residual tumor at radical prostatectomy measuring 0-5 mm). Secondary end points included metastasis-free survival, overall survival, and time to testosterone recovery. RESULTS: Overall, 117 patients were included in the analysis, of whom 78.6% (92) had high risk disease. Following neoadjuvant therapy, 21.4% (25) had 0-5 mm of residual tumor, including 9.4% (11) with a pathological complete response. Overall, 49 patients (41.9%) experienced biochemical recurrence and the 3-year biochemical recurrence-free rate was 59.1% (95% CI 49.0-67.9). Of the 25 patients with an exceptional pathological response, 2 patients (8.0%) developed biochemical recurrence while 51.1% of nonresponders (47/92) developed biochemical recurrence. Testosterone recovery was observed in 93.8% of patients (106/113). PTEN loss and intraductal carcinoma were associated with shorter time to biochemical recurrence. CONCLUSIONS: In this pooled analysis of prospective trials, we demonstrate that exceptional pathological response following neoadjuvant therapy is associated with a favorable impact on biochemical recurrence. PTEN loss and intraductal carcinoma were associated with biochemical recurrence. Additional followup is warranted to evaluate the impact on long-term outcomes.