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

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.

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.

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.

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.