Characteristics and outcomes of observed versus resected pancreatic neuroendocrine tumors.

Background: Pancreatic neuroendocrine tumors (pNETs) are a rare group of tumors with a wide range of clinical presentations. pNETs may present as incidentally discovered slow-growing tumors or as more aggressive tumors with metastatic potential. The mainstay of treatment is surgical resection; however, some have argued that observation can be considered for small, nonfunctional tumors. The objective of this study was to compare patients with pNETs who underwent initial resection versus observation to better understand tumor characteristics that favor either treatment approach. Methods: A retrospective review was performed of patients diagnosed with pNETs at a tertiary referral center from 2018 to 2023. Information on the patient and tumor, disease and treatment course, and outcomes was collected. Results: Forty-three patients were included in the study; 33% underwent initial resection, 37% underwent observation, and 30% underwent surgical resection following a period of observation (delayed resection). Patients who underwent initial resection were more likely to be younger with fewer comorbidities and have symptomatic or functional tumors. Patients with tumors >2 cm were more likely to have a postoperative complication. In a subgroup of patients with incidentally discovered tumors ≤2 cm, 33% underwent delayed resection and did not experience any postoperative complications; 66% underwent observation, and none had progression of their disease over the follow-up period of 17 months. Conclusion: While surgical resection remains the mainstay of treatment for pNETs, a period of observation in select individuals with small, incidentally discovered pNETs may also be considered safe. Management with surgical resection or initial observation must be an individualized decision and may be optimally supported with formal multidisciplinary tumor board discussion.