Reassessment of the Chromogranin-A Cut-off as a Biomarker for Gastroenteropancreatic Neuroendocrine Tumors in a Chilean Cohort

Plasma chromogranin A (CgA) is the most accurate diagnostic bio-marker for neuroendocrine tumors (NETs). However, variations in the cutoff parameters for CgA detection have resulted in non-comparable data across various countries. Notably, most Chilean patients are diagnosed with stage IV NETs, suggesting that the current consensus cut-off criteria may be insufficient for detecting early-stage cases. Aim: To reassess chromogranin A for the diagnosis of endocrine neoplasms in a Chilean population. Materials and Methods: This study involved measuring CgA levels in a Chilean cohort comprising a retrospective group of patients with NETs (n = 76) and healthy subjects (n = 70), totaling 146 individuals. CgA levels were assessed at diagnosis and recruitment utilizing a competitive enzyme-linked immunosorbent assay (ELISA) with polyclonal antibodies (ED kit). Results: Patients diagnosed with NETs exhibited increased CgA levels, with those in advanced stages demonstrating even higher levels. By employing the ROC curve and determining Youden's index, we established a plasma CgA cutoff value of 89 (ng/ml), which is lower than the threshold previously used for diagnosing Chilean patients. Elevated CgA levels were associated with a more accurate diagnosis of NETs. Conclusion: Based on these findings, we propose a reassessment of the cutoff detection values to enhance the diagnosis, follow-up, and progression tracking of NETs in the Chilean population.