Circulating chromogranin A in the assessment of patients with neuroendocrine tumours. A single institution experience

Background: Chromogranin A (CgA) is a secretory protein present in dense-co re vesicles of neuroendocrine (NE) cells. Its ubiquitous presence in NE tis sues makes it a suitable circulating marker of neoplasms of NE origin. Patients and Methods: Plasma CgA was determined in 178 patients with NE tum ors and in 36 patients with non-endocrine malignancies. Circulating CgA was also serially evaluated in 39 NE cancer patients with advanced disease sub mitted to systemic therapy and in 14 patients with no evidence of disease ( NED). Results: Supranormal CgA values were found in 81% of patients with advanced NE tumors and in only 91% of NED cases. Plasma CgA in patients with well d ifferentiated NE tumors, such as carcinoids, carcinoma of gastrointestinal tract, pheocromocytoma, pancreatic NE carcinoma (either functioning or not functioning), medullary thyroid carcinoma and NE tumors from various primar y sites, was higher and more frequently elevated than in patients with smal l-cell lung cancer (P < 0.001). Plasma CgA did not discriminate patients wi th NE from those with non NE neoplasms since it was found elevated in 44% o f the latter cases. Plasma CgA pattern correlated with the disease response in patients submitted to cytotoxic treatment and with changes in clinical symptomathology in patients receiving somatostatin analogs. Conclusions: Our data confirm that CgA is the best circulating neuroendocri ne marker available up to now available for the management of differentiate d neuroendocrine malignancies irrespective of tumor location and functional status. CgA plasma levels could also identify the coexistence of neuroendo crine differentiation in the context of non-endocrine malignancies. Circula ting CgA seems to be less useful in undifferentiated tumors such as small-c ell lung cancer.