Chromogranine A and neuron-specific enolase as the main predictors of survival for hormone-refractory prostate cancer (HRPC) patients

Abstract

15594 Background: Clinical studies suggested that the extent of neuro-endocrine differentiation in prostate cancer increases with tumor progression and the development of androgen refractory status. Chromogranine (CgA) and neuron-specific enolase (NSE) are currently explored as surrogate markers. Methods: Eligible chemonaive HRPC patients (pts) were required to have an ECOG performance status (PS) ≤ 2. Before chemotherapy initiation, we quantified NSE, CgA and PSA in the venous blood using commercial kits. We evaluated the impact of baseline NSE, CgA and PSA on overall survival (OS) using multivariate Cox regression analysis, stratified by chemotherapy regimen. Secondary, we studied the correlation between NSE, CgA, PSA and other important variables as age, Gleason score, hemoglobin, number of metastatic sites and ECOG PS. Results: Data of 39 consecutive HRPC pts treated between December 01–06 in a single French center were analyzed. Chemotherapy was docetaxel-based in 92% of pts. Median age was 71 years (range 51–86) and 79% of pts had bone metastases. Elevated NSE, CgA and PSA were observed in 6, 9 and 30% of pts and median levels were 10.8, 67 and 23.3 ng/mL, respectively. Gleason 8–10 was present in 49% of pts. Significant correlations were observed between NSE and the number of metastatic sites and between CgA and age, hemoglobin and ECOG PS. The baseline PSA was only correlated with Gleason score. Median OS for the entire cohort was 24.4 months (95% CI, 18.8–29.9). Two-year OS was 15% and only 19% of patients are dead. Univariate Cox regression analysis showed only a significant relationship between OS and baseline NSE: hazard ratio= 1.09 (95% CI, 1.03–1.16), P=0.006. No other known prognostic factors are related to outcome. A multivariate model including baseline NSE, CgA, ECOG PS and Gleason score showed a 15% rise of the risk of death related to NSE (borderline P value). Conclusions: NSE was the most powerful predictor of survival for HRPC pts. Our results emphasize the theory that cells secreting NSE are chemoresistant, with a negative impact on OS. No significant financial relationships to disclose.