Chromogranin A assessment in patients with neuroendocrine neoplasm of the small bowel and carcinoid syndrome treated with somatostatin analogues

BACKGROUND: Chromogranin A (CgA) is one of the non-specific markers measured in the biochemical diagnostics of neuroendocrine neoplasms (NENs). OBJECTIVES: To analyze the CgA levels of patients with carcinoid syndrome who are being treated with somatostatin analogues (SSAs), depending on the histologic maturity of the neoplasm, the degree of liver involvement and the stage of the disease. MATERIAL AND METHODS: The study group comprised of 41 patients, including 29 women (70.7%) and 12 men (29.3%). All of the patients had undergone surgical removal of the primary site. Hepatic metastases were found in all patients and they all were treated with SSAs. Chromogranin A concentration was determined using the enzyme-linked immunosorbent assay (ELISA). RESULTS: Among the patients with grade 1 tumors, the mean CgA value was 298.83 ng/mL, whereas in the group with grade 2 tumors, the CgA value was 1498.44 ng/mL, which was a statistically significant difference (p < 0.001). In the group of patients with 10% liver involvement, the mean CgA value was 394.44 ng/mL, whereas in the group of patients with 25% liver involvement, this value was 1,770.63 ng/mL, demonstrating significantly higher values (p < 0.001). Among the patients with a progressing disease, the mean CgA concentration value was 1,620.78 ng/mL, whereas in the group of patients with a stable disease, these were considerably lower, amounting to 230.36 ng/mL (p < 0.001). CONCLUSIONS: Assessing CgA level in patients with carcinoid syndrome is helpful in the diagnostics and monitoring of treatment because CgA values depend on the tumor grade and the severity of the disease.