Zhang, Irene Y.2019-06-242017-052017-09-202017Zhang, Irene Y. 2017. Operative Versus Nonoperative Management of Nonfunctioning Pancreatic Neuroendocrine Tumors. Doctoral dissertation, Harvard Medical School.http://nrs.harvard.edu/urn-3:HUL.InstRepos:40621372Introduction: Surgical resection is the only curative treatment for pancreatic neuroendocrine tumors (PNETs), but pancreatic operations carry a significant morbidity. We investigated whether the resection of small, asymptomatic nonfunctioning PNETs is beneficial. Clinicopathologic factors were retrospectively reviewed for all PNET cases from 1998 to 2014. Methods: Kaplan-Meier survival and multivariable regression analyses were performed. A total of 249 patients had nonfunctioning PNETs with adequate follow-up, of whom 193 were resected and 56 were observed. Median age was 56 years, and 48% of the patients were female. Results: Overall, the resected patients had a significantly longer survival (OS) (p = 0.001). However, for the patients with PNETs ≤ 2.5 cm in size and without metastasis at presentation, tumor size significantly modified the effect of resection on overall survival (p < 0.05). The protective effect of resection increased as tumor size increased. An operation became a significant predictor of overall survival for tumors > 1.5 cm (p = 0.050 or less for larger tumors) but was not significant for tumors < 1.5 cm (p = 0.317 or more for smaller tumors), controlling for age-adjusted Charlson comorbidity index. Conclusion: Resection of nonfunctioning PNETs over 1.5 cm is independently and significantly associated with a longer survival. However, the benefit of resection for tumors under 1.5 cm is unclear.application/pdfenpancreaspancreatic neuroendocrine tumorsurgeryresectionsizeThesis or Dissertation2019-06-24