Background/aims: The WHO 2010 grading system for gastroenteropancreatic neuroendocrine tumors(GEP-NETs) is used to evaluate the malignant potential without clinicopathological information. This study was conducted to examine whether the new index is superior to the previous WHO 2004 classification, e.g.for well-differentiated endocrine carcinoma (WEC),involving clinical information.
Methodology: Between 2000 and 2011, 77 patients with sporadic GEP-NETs were treated at our institution and statistically estimated risk factors for overall survival (OS) were evaluated. Cox proportional hazards regression analyses were performed to estimate risk factors for OS.
Results: Overall 1-, 3- and 5-year survival rates were 92.8%, 78.4% and 76.0%, respectively. Median OS was 551 days in WEC-patients (odds ratio (OR)for OS=13.1, 95% confidence interval (CI)=2.90-59.5;p=0.001). The median OS was 813 days in G3-patients as compared with 1885 days in G1/G2-patients(OR for OS= 2.64, p=0.002). Multivariate analyses according to baseline characteristics revealed WEC as independent risk factor (OR=9.06, p=0.01). WEC was the only predictor of prognosis with an area under the receiver operating characteristic curves of 0.78(p=0.001).
Conclusions: Clinical information was the best predictor for the prognosis of NETs.