Background: Neuroendocrine tumors (NETs) of the gastro-entero-pancreatic (GEP) system are a heterogeneous group of cancers more common in the small intestine. In patients with malignant NETs, especially carcinoids, a number of prognostic parameters have been considered, such as age, clinical symptoms related to the neoplasm, TNM staging and histological grade, as well as urinary 5-hydroxyindolacetic acid (5-HIAA), chromogranin A (CgA) and neuron-specific enolase (NSE) serum levels.
Patients and methods: The data from a series of 14 patients (median age 56 years, range 33-72 years) with gastric (N=8), ileal (N=1), colorectal (N=4) or appendiceal (N=1) malignant carcinoids were retrospectively reviewed.
Results: The specificity of CgA, NSE, and 5-HIAA was 86%, 86% and 93%, while the sensitivity was 64%, 36%, and 36%, respectively. There was no relationship between survival and or urinary 5-HIAA (R=0.12, p=0.45), CgA (R=0.22, p=0.21) nor serum NSE (R=0.12, p=0.76) levels.
Conclusion: The sensitivity of tumor markers is generally low in patients with malignant carcinoids, and both 5-HIAA and CgA levels are independent of survival.