Resection versus expectant management of small incidentally discovered nonfunctional pancreatic neuroendocrine tumors

Background. Sporadic, nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) are diagnosed with increasing frequency. We compared the risk of tumor growth, metastasis, and mortality between patients treated versus those treated expectantly. Method. A retrospective study of patients seen at our institution with sporadic NF-PNETs, with 12 months of follow-up. Kaplan-Meier analysis was performed. Results. Between 1999 and 2014, 35 patients with an incidentally discovered nonfunctional PNET were identified. Twenty underwent resection and 15 were followed with imaging. In the operative group, 8 had NF-PNETs < 2 cm, while 12 had NF-PNETs >= 2 cm. In the nonoperative expectant management by serial imaging group, 10 had NF-PNETs < 2 cm while 5 had NF-PNETs >= 2 cm. Small NF-PNETs (<2 cm) in either the operative or nonoperative groups demonstrated no evidence of progression or metastasis (median follow-up of 27.8 months). Morbidity in the operative group was 35% with pancreatic pseudocyst the most common. Conclusion. Incidentally discovered NF-PNETs < 2 cm in size can be observed safely with serial imaging.