Epidemiologie und Management neuroendokriner Neoplasien unbekannter Herkunft – ein Überblick

Abstract

Abstract Background Neuroendocrine neoplasms (NEN) are rare tumors, mainly located in the lungs, pancreas or gastrointestinal tract. In some NENs the origin remains unidentified. They are referred to as cancer of unknown primary (CUP). Since only 9–14% of NENs are CUP, data about prognosis and therapy is scarce. Therefore, this paper aims to summarize the current knowledge on patients with CUP-NENs. Methods This analysis is a literature review, including the following databases, PubMed and Google Scholar, using the keywords neuroendocrine tumor, cancer of unknown origin, unknown primary, CUP, epidemiology, definition, therapy guidelines, survival. In all, 47 articles were selected and included. Results The available literature indicated that the median age of onset was higher in CUP compared to NENs of known origin. CUP had a comparatively higher rate of poorly differentiated neoplasia. The recommended imaging modality was computed tomography (CT), complemented by positron emission tomography (PET)/CT, using 68Gallium-labeled somatostatin analogues (68Ga DOTATOC, DOTANOC or DOTATATE PET/CT). Surgical resection was suggested as first-line therapy. Other treatment options included chemotherapy, somatostatin analogues, molecular therapy and radiotherapy. Compared to NENs of known origin, CUP were associated with a worse prognosis. Conclusion The current data suggest that CUP-NEN are frequently associated with older age and higher grade compared to patients with known-origin NENs. This reflected a worse prognosis for CUP-NENs.