Sporadic vs. MEN-associated pancreatic neuroendocrine tumors: multi-institutional clinicopathologic comparison

Abstract

Introduction: Clinicopathologic distinctions of Multiple Endocrine Neoplasia (MEN) associated Pancreatic Neuroendocrine Tumor (PNET) are not well established. We sought to improve surgical decision making in MEN-associated PNET. Method: We reviewed a multi-institutional international PNET database for patients with MEN-associated or sporadic PNET. Clinicopathological characteristics were compared. Overall(OS) and disease-free survival(DFS) were analyzed. Propensity score matching reduced bias based on tumor size, t-stage, and age. Results: 651 patients were included(45 MEN1, 606 sporadic). Patients with MEN were diagnosed at a younger age (46vs58 years,p< 0.01), and were more often female (60vs49%,p< 0.01), multifocal (71vs19%,p< 0.01) and higher t-stage (76vs55% stage 4,p=0.034). Lymph node involvement and the presence of metastasis were similar between groups. The rate of total pancreatectomy was 5x higher in the MEN cohort (16vs3%,p=0.004). Median follow-up was 46 months. Survival analysis did not show significant differences between groups. DFS was 126 months in the MEN cohort vs.198 months in the sporadic cohort, but these curves were not statistically different (Figure). After matching was performed, survival remained similar between cohorts (OS median was not reached in either cohort, DFS 126 (MEN) vs 198 (Sporadic) months, p>0.5. Matched patients did not demonstrate differences in lymph node positivity (28vs25%,p=0.913) or presence of metastatic disease (22vs13%,p=0.29). Conclusion: MEN-associated PNET occurs more frequently in younger, female patients, and is associated with multi-focality and high t-stage. Survival for patients with MEN-associated PNET is excellent. Consideration should be given to active surveillance and/or parenchymal-sparing surgical interventions to preserve pancreatic function given the indolence of this disease.