RT Journal Article SR Electronic T1 Prognostic and Predictive Factors for Anti-androgen Withdrawal in Castration-resistant Prostate Cancer JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 4115 OP 4121 DO 10.21873/anticanres.12702 VO 38 IS 7 A1 TOMOHIKO MURAKAMI A1 HIROFUMI OBATA A1 NAOKO AKITAKE A1 MASAKI SHIOTA A1 ARIO TAKEUCHI A1 EIJI KASHIWAGI A1 JUNICHI INOKUCHI A1 KATSUNORI TATSUGAMI A1 MASATOSHI ETO YR 2018 UL http://ar.iiarjournals.org/content/38/7/4115.abstract AB Background/Aim: We aimed to identify prognostic and predictive factors for anti-androgen withdrawal syndrome (AWS) to help guide decisions on anti-androgen withdrawal in castration-resistant prostate cancer (CRPC). Patients and Methods: This study included 95 patients with prostate cancer which progressed to CRPC despite primary androgen-deprivation therapy (ADT). AWS was defined as >50% prostate-specific antigen decline after anti-androgen withdrawal. Associations between AWS, and clinicopathological factors and prognosis were investigated. Results: Among the 95 patients, 84 (88.4%) underwent anti-androgen withdrawal, among whom AWS was recognized in nine (10.8%). Gleason score and response duration to primary ADT were predictors of AWS. Long duration of response to primary ADT was also associated with better progression-free survival [hazard ratio (HR)=0.021, 95% confidence interval (CI)=0.0025-0.14, p<0.0001] and overall survival (HR=0.0042, 95% CI=0.0001-0.089, p<0.0001). Age (HR=7.19, 95% CI=1.08-54.27, p=0.041) and radiological/clinical progression (HR=3.14, 95% CI=1.35-6.43, p=0.010) were associated with worse overall survival. Intriguingly, radiological/clinical progression was associated with the differential effect of anti-androgen withdrawal on overall survival (interaction p=0.031). Conclusion: Patients who suffer radiological/clinical progression are unsuitable candidates for anti-androgen withdrawal.