The Use and Utility of Preoperative Somatostatin Receptor-Based Imaging in Gastroenteropancreatic Neuroendocrine Tumors

BACKGROUND: Contemporary gastroenteropancreatic neuroendocrine tumor (GEPNET) management guidelines recommend routine use of functional imaging preoperatively, but there are few data highlighting trends in functional imaging adoption. This report reviews 24 years of neuroendocrine tumor (NET) experience to describe changes in rates of preoperative functional imaging use and highlights performance differences between functional imaging types in small bowel NETs (SBNET) and pancreatic NETs (PNETs). METHODS: A retrospective single-institution study from 2000 to 2023 identified patients with SBNETs and PNETs treated with surgical resection, cytoreduction, or both who underwent preoperative functional imaging. The primary measurements were frequency of functional imaging use and location of metastases identified on preoperative imaging. RESULTS: The study included 392 SBNET and 208 PNET patients. Preoperative functional imaging was performed for 248 (63.3%) SBNET patients (158 somatostatin receptor [SSTR] positron emission tomography [PET] and 90 Octreoscan) and 113 (54.3%) PNET patients (47 SSTR PET and 66 Octreoscan). There was a significant positive trend over time in functional imaging use in SBNET patients, with an approximate 2.5% yearly increase (p < 0.01) but no significant change in PNET patients during the course of the study (p = 0.82). At presentation, 82.3% (204/248) of the SBNET patients and 54.9% (62/113) of the PNET patients had metastatic disease. Compared with Octreoscan, SSTR PET more frequently identified bone and retroperitoneal nodal metastases. CONCLUSION: Rates of functional imaging use in SBNET patients but not in PNET patients increased significantly during the last 24 years. Patients with SBNETs and PNETs frequently presented with metastatic disease, and SSTR-based functional imaging was extremely helpful in identifying distant disease, intra-operative planning, and further management.