Clinical effect of abiraterone acetate in Korean patients with metastatic castration-resistant prostate cancer according to duration of androgen deprivation therapy.

Purpose: Few data are available concerning the clinical outcome of abiraterone acetate treatment in patients with metastatic castration-resistant prostate cancer (mCRPC) in terms of the duration of androgen deprivation therapy (ADT) before diagnosis of CRPC. We investigated the clinical efficacy of abiraterone acetate according to the duration of ADT.

Materials and methods: We reviewed the medical records of 20 patients with mCRPC who received abiraterone acetate after failure of docetaxel chemotherapy from May 2012 to March 2014 at Seoul National University Bundang Hospital. Clinical factors including prostate-specific antigen (PSA) nadir level, time to PSA nadir, PSA doubling time, PSA response, and modes of progression (PSA, radiologic, clinical) were analyzed. Disease progression was classified according to the Prostate Cancer Working Group 2 criteria.

Results: The mean age and PSA value of the entire cohort were 76.0±7.2 years and 158.8±237.9 ng/mL, respectively. The median follow-up duration was 13.4±6.7 months. There were no statistically significant differences in clinical characteristics between patients who received abiraterone acetate with ADT duration<35 months and those who received abiraterone acetate with ADT duration≥35 months. There were also no significant differences in terms of PSA progression-free survival, radiologic progression-free survival, and clinical progression-free survival between patients with ADT duration<35 months and those with ADT duration ≥35 months.

Conclusions: Although this was a retrospective study with a small sample size, we did not observe any statistically significant differences in the clinical response to abiraterone acetate between mCRPC patients with long ADT duration and those with short ADT duration in terms of disease progression-free survival.