Chromogranin A is a potential prognostic marker in prostate cancer patients treated with enzalutamide

BACKGROUND In this retrospective study, we assessed chromogranin A (CgA) baseline value as a possible factor associated with poor prognosis in metastatic castration-resistant prostate cancer (CRPC). METHODS Thirty-five patients with metastatic CRPC progressing after docetaxel chemotherapy treated with enzalutamide are subdivided into three groups: serum CgA level was normal when <120 ng/ml (group A, n = 10), within three times the upper normal value (UNV) when between 120 and 360 (group B, n = 17), more than three times the UNV when ≥360 ng/ml (group C, n = 8). RESULTS No correlation was observed in three groups among CgA baseline values and PSA response rates (RR) (P = 0.4648), whereas a significative difference was associated with median progression-free survival (PFS) and overall survival (OS) among three CgA groups (P = 0.0301 and P = 0.0011, respectively). In the multivariate analysis, PSA RR (nonresponsive vs. responsive) and CgA levels (group 3 vs. groups 1 + 2) were predictors of OS (P = 0.0029 and P = 0.0025, respectively), whereas they only were not significantly correlated with PFS, even had a borderline significance (P = 0.0628 and P = 0.0772, respectively). CONCLUSIONS In CRPC patients treated with enzalutamide, the evaluation of serum CgA levels could be an useful prognostic factor because of the strong association between CgA value more than three times the UNV and clinical outcome, independently from PSA response.