Prostate-specific antigen after neoadjuvant androgen suppression in prostate cancer patients receiving short-term androgen suppression and external beam radiotherapy: pooled analysis of four NRG Oncology RTOG randomized clinical trials

Abstract Purpose To validate if prostate specific antigen (PSA) level after neoadjuvant androgen suppression (neoAS) is associated with long-term outcome after neoAS and external radiation therapy (RT) with concurrent short-term AS in prostate cancer patients. Methods 2404 patients treated with neoAS prior to RT and concurrent AS (without post-RT AS) were pooled from trials A, B, C, and D. Multivariable models were used to test associations between the pre-specified dichotomized post-neoAS, pre-RT PSA (≤0.1 vs. >0.1 ng/mL) groupings and clinical outcomes. Results Median follow-up for surviving patients was 9.4 years. Median post-neoAS, pre-RT PSA was 0.3 ng/mL, with 32% of patients ≤0.1 ng/mL. Race, Gleason score, T-stage, N-stage, pre-treatment PSA, and duration of neoAS were associated with the groups of patients with PSA ≤0.1 and >0.1 ng/mL. In univariate analyses, post-neoAS, pre-RT PSA >0.1 ng/mL was associated with increased risks of biochemical failure (hazard ratio [HR] 2.04; p 0.1 ng/mL was independently associated with increased risk of biochemical failure (HR 2.00; p Conclusion Patients with PSA >0.1 ng/mL after neoAS and before RT start had less favorable clinical outcomes than patients with PSA was ≤0.1 ng/mL. The role of post-neoAS, pre-RT PSA presently, relative to PSA obtained along the continuum of medical care, is not presently defined, but could be tested in future clinical trials.