Small, nonfunctioning, asymptomatic pancreatic neuroendocrine tumors (PNETs): Role for nonoperative management

Background: Controversy exists regarding the optimal management of incidentally discovered, small pancreatic neuroendocrine tumors (PNETs). Our aim was to review the outcomes of patients who underwent nonoperative and operative management. Methods: We retrospectively reviewed patients with nonfunctioning PNETs at our institution from January 1, 2000 to June 30, 2011. Patients were included if the tumor was sporadic and <4 cm without radiographic evidence of local invasion or metastases. Results: Nonoperative patients (n = 77, median age, 67 years; range, 31-94) had a median tumor size of 1.0 cm (range, 0.3-3.2). Mean follow-up (F/U) was 45 months (max. 153 months). Median tumor size did not change throughout F/U; there was no disease progression or disease specific mortality. In the operative group (n = 56, median age, 60 years; range, 27-82), median neoplasm size was 1.8 cm (range, 0.5-3.6). Mean F/U was 52 months (max. 138 months). A total of 46% of the operative patients had some type of complication, more than half due to a clinically significant pancreatic leak. No recurrence or disease specific mortality was seen in the operative group, including 5 patients with positive lymph nodes. Conclusion: Small nonfunctioning PNETs usually exhibit minimal or no growth over many years. Nonoperative management may be advocated when serial imaging demonstrates minimal or no growth without suspicious features.