Prognostic factors in gastroenteropancreatic neuroendocrine tumors - A retrospective multivariate analysis

Abstract

4086 Background Only few data exist on long-term outcome and independent prognostic factors of neuroendocrine tumors (NET) of the gastroenteropancreatic (GEP) system. Low incidence, heterogeneous classifications and various treatment modalities influence the sparsity of epidemiologic data. Here we present long-term outcome data from a large cohort of a referral center. Methods Descriptive statistical analysis of retrospective data from 392 patient records of histologically proven GEP-NET treated at our institution from 1980–2003 was followed by a multivariate analysis after adjustment for gender and age using a Cox-regression-model. Among the studied parameters were localization and size of the primary tumor, presence of a hypersecretion syndrome, clinical symptoms and metastasis at initial diagnosis, and surgical therapy. We analyzed the whole study cohort and the subgroup for which histopathological information about the proliferation fraction (ki67-index) was known. Results Localization of the primary tumor was foregut in 47% (pancreas 25%), midgut in 38% (jejunoileum 29%), hindgut in 4%, and unknown in 10%. In 73% the NET had already metastasized at initial diagnosis and 23% of the patients had symptoms of hormone hypersecretion. The ki67-index was distributed as follows (n=255): <5%: 52%, 5–10%: 25%, >10%: 23%. Mean follow-up was 25.6 months. 96 patients died during the observation period, 85% of NET-associated causes. The results of the multivariate analysis are displayed in the table. Conclusion While unknown size of the primary, a primary tumor larger than 2.5 cm, and a ki67-index >5% (with even higher significance for GEP-NET with a ki67-index >10%) were independent prognostic factors of an unfavourable outcome, a surgical intervention with curative intent proved to indicate a favourable prognosis. Thus, these informations are of crucial importance for the management of patients with GEP-NET. No significant financial relationships to disclose.