Early prostate-specific antigen response post-abiraterone as predictor of overall survival in metastatic castrate-resistant prostate cancer.

Abiraterone is an important agent in the treatment of advanced prostate cancer. Early changes in prostate-specific antigen while on abiraterone in patients with metastatic castrate-resistant prostate cancer potentially have financial and health implications for patients. Limited data is available on early prostate-specific antigen change and subsequent survival given phase III trials did not measure prostate-specific antigen changes before 12 weeks.

A single-center retrospective study was performed. Metastatic castrate-resistant prostate cancer patients treated with abiraterone (without prior enzalutamide) at Tulane Cancer Center were reviewed with a focus on early prostate-specific antigen decline and relationship to overall survival.

A total of 110 patients were analyzed for prostate-specific antigen response of ≥ 30 and > 50% at 4, 8, and 12 weeks. A prostate-specific antigen response of either > 30% or > 50% at 4, 8, or 12 weeks was associated with improved overall survival at all time points except > 50% decline at 8 weeks. Multivariate analysis indicated, for all time points, that early prostate-specific antigen declines were predictive of overall survival. The neutrophil to lymphocyte ratio and docetaxel pretreatment also were predictive in many, but not all, of the multivariate analyses.

A > 30% or > 50% prostate-specific antigen decline at 4, 8, or 12 weeks provides important information regarding subsequent overall survival for patients with metastatic castrate-resistant prostate cancer. While these data require validation with a large, multi-institutional trial, they can provide physicians with information regarding prognosis and the timing of expected outcomes. These data affirms the notion that prostate-specific antigen responses as early as 4 weeks after abiraterone initiation can be used to inform both patients and physicians about metastatic castrate-resistant prostate cancer outcomes after initiating treatment with this important but costly therapeutic choice.

BMC cancer. 2019 May 31*** epublish ***

Joshua P Schiff, Patrick Cotogno, Allison Feibus, Peter Steinwald, Elisa Ledet, Brian Lewis, Oliver Sartor

Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Ave., SL-42, New Orleans, LA, 70112, USA., Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Ave., SL-42, New Orleans, LA, 70112, USA. .