[Plasma chromogranin-A (CgA)--a potential marker for diagnosis, monitoring and management of prostate cancer patients].

INTRODUCTION

Neuroendocrine differentiation of prostatic adenocarcinoma is a recognized phenomenon, which is believed to parallel tumor progression to hormone refractory state. Circulating CgA levels were shown to reflect neuroendocrine differentiation and were found to correlate with the stage and the state of hormone refractoriness. Hence, CgA may become a marker for diagnosis, monitoring and management of prostate cancer patients.

PATIENTS AND METHODS

CgA level was measured in plasma samples which were obtained from 40 patients with prostate cancer, using the ELISA kit (DAKO, Glostrup-Denmark). The normal range of CgA was 2-18, SD = 4. The normal threshold was hence set to 26 u/L calculated as upper normal level + 2SD. Additionally, serum levels of PSA, CEA, CA-125, CA-15.3 and CA-19.9 were measured at that time. Clinical data was collected from medical records.

RESULTS

Overall, CgA was elevated in 18 patients (45%) including 25% of the patients with organ confined disease, 52.9% with locally advanced disease, 71.4% of the patients with metastases, 75% of the patients with hormone refractory prostate cancer and 23.1% of patients with hormone sensitive disease (p = 0.009). Mean CgA and PSA levels among patients with elevated CgA was 100.2 u/L (27-717) and 301 ng/ml (4.5-1450) respectively. In comparison to 18.8 u/L (14-26) and 14.7 ng/ml (2.6-59.7) respectively, in patients with CgA within the normal range (p < 0.05). PSA at the time of CgA sampling did not differ among the two groups.

CONCLUSIONS

In this study high plasma CgA levels correlated with known poor prognostic factors including advanced and metastatic disease at the time of presentation, high pretreatment PSA levels and hormone refractoriness. CgA levels which reflect neuroendocrine differentiation of prostatic carcinoma may have a diagnostic, therapeutic and prognostic role in the management of prostate cancer patients.