Evaluating the role of postoperative long-acting somatostatin analog therapy in patients with metastatic neuroendocrine tumors undergoing surgical debulking.

Abstract

The optimal timing of postoperative somatostatin analog resumption in patients with metastatic gastroenteropancreatic neuroendocrine tumors after surgical debulking is unknown and varies between institutions. We hypothesized that somatostatin analog resumption can be safely deferred after debulking in select patients. We performed a retrospective cohort study of patients with well-differentiated gastroenteropancreatic neuroendocrine tumors with liver metastases who underwent liver debulking, synchronously or metachronously with primary tumor resection at an academic referral center (2019-2023). Clinicopathologic characteristics and progression-free survival were compared between patients who resumed somatostatin analog within 90 days of surgery and those who did not (never resumed or resumed >90 postoperative days). Of 83 patients, 56 (68%) had small bowel neuroendocrine tumors, whereas 27 (32%) had pancreatic neuroendocrine tumors. Twenty-seven (33%) resumed somatostatin analog within 90 days of debulking. The somatostatin analog resumption group had higher frequency of pancreatic neuroendocrine tumors (52% vs 23%, P = .01), extrahepatic metastases (70% vs 36%, P = .005), and higher Ki-67 index (median 4% vs 2%, P = .03). Somatostatin analog resumption was associated with worse progression-free survival (median 13 vs 21 months, P = .048). Pancreatic location (hazard ratio = 2.2, P = .003) and osseous metastases (hazard ratio = 2.0, P = .04) were independent predictors of shorter progression-free survival after debulking. Among patients who did not immediately resume somatostatin analog, small bowel neuroendocrine tumors had longer progression-free survival (median 34 vs 16 months, P = .02). Patients with small bowel neuroendocrine tumors without osseous metastases undergoing surgical debulking experience long progression-free survival and might therefore benefit from delaying postoperative somatostatin analog resumption. Our findings provide foundational data for a prospective trial.