Prognostic validation of the WHO 2010 grading system in pancreatic insulinoma patients

The purpose of this study was to evaluate the prognostic potential of the World Health Organization (WHO) 2010 grading system in patients with pancreatic insulinomas. This was a retrospective study that analyzed the overall survival of 85 pancreatic insulinoma patients treated at our Institute between May 2002 and March 2013. The mean age of our patient cohort was 44.26 ± 13.82 years, with the gender split at 30 males and 55 females. Median survival time of the cohort, post-surgery, was 100.23 ± 18.18 months. Among the 85 patients, histopathological analyses revealed 52 Low Grade (G1) neuroendocrine tumors (NET), 23 Intermediate Grade (G2) NET, and 10 High Grade (G3) Neuroendocrine carcinomas (NEC) according to the WHO 2010 grading classification. Significant difference for overall survival was observed between the NET G1 and NEC G3 groups (P<0.01), and the NET G2 and NEC G3 groups (P<0.019). In addition, our data showed that overall survival was significantly correlated with the European Neuroendocrine Tumor Society (ENETS) tumor-node-metastasis (TNM) staging system, and in multivariate analysis, the diameter of tumor was found to be significantly correlated with survival (P=0.038). These findings provide additional validation for the prognostic value of using the WHO 2010 grading system, specifically with regard to pancreatic insulinomas.