Neoadjuvant Hormone Therapy for Radical Prostate Radiotherapy: Bicalutamide Monotherapy vs. Luteinizing Hormone–Releasing Hormone Agonist Monotherapy: A Single-Institution Matched-Pair Analysis

Abstract

BackgroundThe purpose of this study was to compare the prostate-specific antigen (PSA) response to either neoadjuvant bicalutamide (BC) monotherapy or neoadjuvant luteinizing hormone–releasing hormone agonist (LHRHa) monotherapy and the subsequent effect on biochemical failure–free survival (BFFS) in men receiving radical radiotherapy (RT) for localized prostate cancer. Patients and MethodsThis was a retrospective review of consecutive men treated with BC monotherapy before radical prostate RT who were individually case-matched to men treated with neoadjuvant LHRHa monotherapy. PSA kinetics and absolute pre-RT posthormone PSA (PRPH-PSA) level and subsequent BFFS were analyzed. ResultsSixty-five men treated with BC monotherapy with a median follow-up of 44 months were individually matched with 65 men treated with LHRHa with a median follow-up of 54 months. Statistically significant differences were noted between groups in the PRPH-PSA, with a mean of 2.9 ng/mL (0.1-11.2 ng/mL) for patients receiving BC treatment and 1.8 ng/mL (0.1-11.1 ng/mL) for patients receiving LHRHa treatment (P < .001). A PRPH-PSA of < 1.0 and < 0.1 ng/mL was seen in 16 (24.6%) and 2 (3%) of the patients receiving BC and 34 (52.3%) and 3 (4.6%) patients receiving LHRHa, respectively. There were no significant differences between groups in either PSA halving time or velocity. Phoenix biochemical failure occurred in 10 (15.4%) and 8 (12.3%) patients receiving BC and patients receiving LHRHa, respectively. Neither PRPH-PSA level nor PSA kinetics during the neoadjuvant period predict for subsequent BFFS at this duration of follow-up. ConclusionsAlthough neoadjuvant BC therapy did not result in equivalent PRPH-PSA suppression when compared with neoadjuvant LHRHa alone, there was no difference in biochemical failure rates between cohorts at 50 months' median follow-up. Longer follow-up is required.