Lack of Accuracy of Circulating Chromogranin A in the Preoperative Diagnosis of Lung Neuroendocrine Tumors.

INTRODUCTION: While the role of the circulating neuroendocrine markers Chromogranin A (CgA) in the diagnosis of neuroendocine differentiation of a neoplasm or in predict post-surgical recurrences in gastroenteropancreatic (GEP) neuroendocrine tumors (NET) has been established, the same role in thoracic neuroendocrine tumors (TNET) remain to be clarified AIM: The aim of this study was to establish the diagnostic accuracy of CgA in TNET PATIENTS AND METHODS: The study has been performed in a court of 2461 pz in which circulating CgA was evaluated in our laboratory between 2003 and 2010. The dosage was performed with the RIA Kit, CIS-Bio International, Gif-sur-Yvette, France (normal range 19,4-98,1 ng/ml ). RESULTS:. Among lung cancer patients an increase above normal range was identified very often in NSCLC (non small cell lung cancer) (62 % false positivity). Only 14 % of TNET were associated with a significative increase above the normal range (true positivity), 9 % in bronchial carcinoids and 5 % for SCLC (small cell lung cancer). Another 10 % of different lung tumors was associated with false positivity. CONCLUSIONS: This data evidences the absolute lack of specificity of the increase of levels of circulating CgA for the diagnosis of neuroendocrine differentiation of a lung tumor, due to the know limits of this marker. The necessary increase of the upper normal limit to reach an acceptable specificity is counterbalanced by a consequent reduction of an already very low sensitivity. According to these data the utility of this marker appear limited in the clinical management of TNET.