Chromogranin A als Parameter bei der Diagnosestellung und in der Verlaufsbeobachtung von Patienten mit gastroenteropankreatischen neuroendokrinen Tumoren des hindgut

Background: Chromogranin A is a well-established marker to diagnose and follow up patients with gastroenteropancreatic neuroendocrine tumors (GEP-NET). Recently it has been shown that plasma levels of CgA, especially increasing rapidly, correlate with tumor load and predict survival of patients with GEP-NET of the midgut. Due to lack of confirmed information about and the low incidence of GEP-NET of the hindgut, it is assumed that both tumor entities behave similarly concerning clinical behaviour and expression of marker proteins and can therefore be screened and treated similarly. One of the work´s intentions was to figure out the importance of CgA for histological staining as well as a serum marker for GEP-NET of the hindgut and to compare with those of midgut tumors. Material and methods: For this work data of 28 patients with GEP-NET of the hindgut listed in the Mar-burg GEP-NET register was evaluated retrospectively. These patients were fol-lowed up regarding to serum levels of tumor markers like CgA, Serotonin, 5-HIAA and CEA, tumor progression, survival and onset of tumor related compli-cations. Results: It could be shown that CgA is a good marker for the histological diagnosis but poor for follow up as only few patients exhibit elevated serum levels of CgA. Serum levels do rarely increase in case of progression. In contrast to midgut GEP-NET there is no correlation of CgA-levels and tumor burden or overall sur-vival of patients with hindgut GEP-NET. CgA is not suitable to mirror tumor bur-den or prognosis of patients with GEP-NET of the hindgut. Neither do markers like Serotonin, 5-HIAA and CEA reflect the tumor´s progress nor the patients´ outcome. Therefore GEP-NET of the midgut and the hindgut behave differently concerning the examined tumor markers. Patients with GEP-NET of the hindgut display a relatively good prognosis resulting in a 5-year-survival rate of 71%. Three subgroups were identified differing immensely in prognosis. One subset of patients, whose tumors are characterized by a high proliferation rate (Ki-67 >30%) and dedifferentiation (G3), exhibit a very poor prognosis with a 5-year-survival rate of 14%. The carcinoid heart disease as a frequent and life threat-ening complication of carcinoids is not likely in GEP-NET of the hindgut. This work shows that GEP-NET of the midgut and the hindgut are different entities and should not be taken together as one group and are not to be treated similarly as they differ immensely concerning clinical behaviour, marker expression, screening and treating pathways.