Time to Castration Resistance Is an Independent Predictor of Castration-resistant Prostate Cancer Survival

Background/Aim: Easily assessable clinical predictors of response to chemotherapy in advanced castration-resistant prostate cancer (CRPC) are few. The objective of this retrospective study was to search for and identify such candidate predictors of outcome. Patients and Methods: A retrospective analysis of clinical data of CRPC patients entered in the Clinical Therapeutics' departmental prostate cancer database from 1996-2009 was performed. Univariate and multivariate analyses for progression-free survival and overall survival included patients receiving both docetaxel- and non-docetaxel-containing regimens. Results: From 1996 until June 2009, 286 out of 313 patients in our database were treated with chemotherapy. Prostate-specific antigen (PSA) reduction > 30% correlated with improved survival irrespective of treatment. Beyond previously reported predictors, i.e. baseline PSA > 30 ng/dl, hemoglobin below 10 mg/dl, weight loss, poor performance status, elevated lactic dehydrogenase and alkaline phosphatase, and time to CRPC of less than or equal to two years was associated with a poor overall survival and shorter progression-free survival upon univariate analysis. Pain was associated with shorter survival. Multivariate analysis confirmed time to CRPC, lactate dehydrogenase and alkaline phosphatase as independent predictors of overall and progression-free survival. Conclusion: Time to castration resistance is an important predictor of outcome in CRPC. PSA reduction > 30% predicts survival improvement following chemotherapy for CRPC regardless of chemotherapy applied.