ABSTRACT
OBJECTIVE: To determine the value of serum chromogranin A (CgA), a marker of neuroendocrine differentiation, for monitoring prostate cancer: CgA levels were related to three other tumour markers, i.e. total prostate-specific antigen (tPSA), prostatic acid phosphatase (PAP), neurone-specific enolase (NSE), and to testosterone, to assess the importance of hormone withdrawal. PATIENTS AND METHODS: Serum samples (218) were obtained from 118 patients with prostate cancer, including 111 patients with advanced prostate cancer: 103 presented to our centre for systemic radionuclide therapy of painful skeletal metastases. CgA concentrations were measured using a new immunoradiometric assay (IRMA: Cis Bio International, Gif sur Yvette, France) and a threshold of 70 ng/mL was determined after receiver operating characteristic curve analysis. Testosterone was also measured with an IRMA assay; tPSA, PAP and NSE were assayed using the time-resolved amplified cryptate emission. RESULTS: Serum marker levels were high in 64% of the patients for CgA, 24% for NSE, 89% for tPSA and 81% for PAP. Patients resistant to endocrine treatments and with elevated tPSA (i.e. hormone-independent) showed increased CgA and NSE in 62% and 29%, respectively. Patients with hormone-dependent prostate cancer (i.e. with a normal tPSA level) had elevated CgA in 59% but no abnormal NSE. All patients of the latter group except one showed clinical progression of their disease. However, the mean (SD) concentrations of CgA in hormone-independent (146) or hormone-dependent (22) patients, at 185.3 (449.1) and 160.9 (293.9) ng/mL, respectively, were not statistically different (P=0.8, Mann-Whitney U-test). For 30 patients, blood samples were drawn and markers measured before and after systemic radionuclide therapy. There was a significant increase in the CgA and tPSA concentrations after treatment (P=0.0146 and 0.0025, respectively). CONCLUSIONS: In association with tPSA, serum CgA appears to be a promising marker for monitoring patients with prostate cancer.
