The Role of Chromogranin A (CgA) in Monitoring Patients with Prostate Cancer Under Androgen Deprivation Therapy: Comparison with Prostatic Specific Antigen (PSA)

Introduction: Neuroendocrine cells of the prostate are regulatory cells containing biogenic amines and certain neuropeptides such as chromogranin A (CgA). In the present study we evaluated the usefulness of serum CgA for monitoring prostate cancer progression. CgA levels were correlated to serum Prostate Specific Antigen (PSA) levels, bone scan findings and Gleason score. Methods: In this study we evaluated 122 patients with prostate cancer (PCa) diagnosed with prostate biopsy and 40 blood donors serving as the control group (CG). In both groups we measured serum CgA and PSA values. All PCa patients had locally advanced or metastatic disease and received complete androgen blockade. In the PCa group bone scanning with 925 MBq Tc-99m-MDP revealed the presence of bone metastatic lesions in 53 patients (32 with more than three hot spots and 21 with less than three hot spots), while the remaining 69 patients had no bone metastases. At one-year follow-up we re-evaluated serum CgA, PSA and bone scans in both groups. Results: The serum levels of CgA and PSA were significantly higher in patients with PCa and bone metastases compared to patients with PCa without bone metastases (p<0.001). Elevated serum levels of CgA, higher than those of PSA, were found in patients with multiple bone metastases and Gleason score >7. Sensitivity and specificity values were 65% and 90% respectively for CgA alone (at 70nmol/L). The sensitivity and specificity of both studies combined (CgA and PSA) were increased to 88% and 97% respectively. Conclusions: Serum CgA is emerging as a potentially valuable marker for predicting the presence of bone metastases in patients with PCa. CgA combined with PSA improves the accuracy for predicting progression of the disease for patients with advanced PCa.