Enucleation for pancreatic neuroendocrine tumors: short- and long-term outcomes in a forty-year single-center experience

Background: Surgery plays a key role in the treatment of pancreatic neuroendocrine tumors (PanNETs). Enucleation combines a radical resection with the sparing of healthy pancreatic parenchyma. Methods: To evaluate short- and long-term outcomes of open enucleation for PanNETs, clinical records of patients operated on from 1979 to 2021 in our Pancreatic Surgical Unit were retrieved retrospectively. Results: Out of 246 PanNETs operated on, 62 (25%) patients underwent enucleation: 39 (63%) women and 23 (37%) men, averaging a mean of 55 (SD, 14) years. Pancreatic NETs were mostly insulinomas (65%), located in the head/uncinate process (61%), and grade 1 (55%), with a median size of 1.5 (IQR, 1.0-1.8) cm. Median operation time was 180 (IQR, 150-205) minutes, and median intraoperative blood loss was 100 (IQR, 20-200) mL. Pancreatic fistula (all grade B) occurred in ten (16%) patients. One (1.6%) reoperation was required for evisceration. Median hospital stay was 10 (IQR, 7-15) days. There was no postoperative mortality. Median follow-up was 153 (IQR, 91-278) months, with seven (11%) patients developing new onset diabetes; however, no exocrine insufficiency occurred. Fourteen (23%) patients died of unrelated causes after a mean overall survival of 219 (SD, 152) months. Conclusions: Enucleation of PanNETs resulted in excellent long-term results for both pancreatic function and oncological outcomes. In open surgery, postoperative morbidity is not negligible, but it does not affect patients' prognosis.