Treatment and Outcome of Extra-Appendiceal Gastrointestinal Neuroendocrine Tumors

Complete surgical resection and localized disease are associated with a favorable clinical outcome.[2,7]

In one retrospective single-institution study, the 5-year relapse-free survival rate was 41% for patients with extra-appendiceal neuroendocrine tumors. The overall survival (OS) rate was 66%.[3]

Treatment options for resectable extra-appendiceal neuroendocrine tumors include the following:

Treatment options for unresectable or multifocal extra-appendiceal neuroendocrine tumors include the following:

SSTR2 ligands include octreotide, long-acting repeatable octreotide, and lanreotide. Octreotide is not practical for therapy because its short half-life necessitates frequent administration. Long-acting, repeatable octreotide and lanreotide have been evaluated in prospective, randomized, placebo-controlled trials.[10,11] Patient age was not specified in the first trial, and eligibility was restricted to age 18 years and older in the second trial. Neither agent produced significant objective responses in measurable tumors. Both agents were associated with statistically significant increases in progression-free survival and time to progression, and both agents are recommended for the treatment of unresectable extra-appendiceal neuroendocrine tumors in adults.

A phase III trial included 231 patients with advanced or metastatic extra-appendiceal neuroendocrine tumors. Patients were randomly assigned to treatment with lutetium Lu 177 (177Lu)-DOTATATE plus long-acting octreotide or high-dose long-acting octreotide (control group). While the median OS did not reach statistical significance, there was an 11.7-month difference, with 48.0 months (95% confidence interval [CI], 37.4–55.2) in the 177Lu-DOTATATE group and 36.3 months (95% CI, 25.9–51.7) in the control group.[16] The U.S. Food and Drug Administration approved the use of 177Lu-DOTATATE for children aged 12 years and older with somatostatin receptor–positive gastroenteropancreatic neuroendocrine tumors.

Embolization, peptide receptor radionuclide therapy, mTOR inhibitors, and TKIs have been used for treatment.[9,12-14]

Conventional cytotoxic chemotherapy appears to be inactive.[3]