Outcome of Debulking the Mesenteric Mass in Symptomatic Patients with Locally Advanced Small Intestine Neuroendocrine Tumors

Background: Approximately 10% of patients with small intestine neuroendocrine neoplasms (SI-NENs) present with locally advanced, unresectable symptomatic disease. The present study analyzed the results of debulking of the mesenteric mass in such patients. Methods: Patients operated on for locally advanced SI-NEN disease were identified from the prospective database of the ENETS Center of Excellence Marburg based on the review of imaging results and operative notes. "Locally advanced" was defined as mesenteric disease involving the mesenteric root above the level of the horizontal part of the duodenum and/or extending into the retroperitoneum. Patient characteristics, operations, and outcomes were retrospectively analyzed. Results: 29 of 202 (14%) operated SI-NEN patients (79% male) operated on, with a median age of 63 (46-78) years, had symptomatic locally advanced disease and presented with either abdominal pain (76%) and/or symptoms of obstruction (38%). Imaging revealed a mesenteric mass >10 mm above the level of the pars descendens duodeni in 15 (52%) patients, with tumor-related obstruction of the superior mesenteric vein in 17 (59%) patients. Fourteen (48%) patients had had previous surgery with primary tumor resection (n = 10) or diagnostic or bypass procedures (n = 4). Debulking of the mesenteric mass with (n = 26) or without (n = 2) bowel resection was performed 28 patients; the remaining patient underwent only resection of the ischemic bowel. Median operating time was 262 (156-411) minutes. Four (14%) patients had clinically relevant postoperative complications; one patient died perioperatively. A total of 27/29 (93%) patients reported improvement in preoperative abdominal symptoms. After a median follow-up of 28 (1-142) months, 21 (72%) patients were alive with disease. Conclusions: Debulking of the mesenteric mass in locally advanced symptomatic SI-NENs is a challenging procedure, but most patients benefit in terms of bowel symptoms.