Neoadjuvant hormone therapy for radical prostate radiotherapy: bicalutamide monotherapy vs. luteinizing hormone-releasing hormone agonist monotherapy: a single-institution matched-pair analysis

Abstract

Background: The 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 methods: This 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.

Results: Sixty-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.

Conclusions: Although 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.