Rectal neuroendocrine tumors: Can they be observed?

Background: Studies comparing approaches to managing rectal neuroendocrine tumors are underpowered by institutional series. The efficacy of expectant management relative to local excision and radical resection is poorly defined.

Methods: We queried the National Cancer Database to identify patients presenting with non-metastatic rectal neuroendocrine tumors between 2004 and 2019. Multivariable regression was used to identify factors associated with expectant management. Cox modeling was used to identify factors associated with all-cause mortality. Patients undergoing expectant management were 1:1:1 propensity score matched for demographics and comorbid disease to those undergoing radical resection and local excision. The Kaplan-Meier method was used to compare overall survival profiles for matched cohorts.

Results: A total of 6,316 patients met the inclusion criteria. Of these, 5,211 (83%) underwent local excision, 600 (9.5%) radical resection, and 505 (8%) expectant management. On multivariable regression, factors associated with expectant management included Black race, government insurance, and tumor size <2.0 centimeters. On Cox modeling, factors associated with mortality included age >65 years, male sex, government insurance, comorbidity score >0, tumor size >2 centimeters, and poorly differentiated histology. On comparison of matched cohorts: patients undergoing radical resection had longer hospitalizations and higher readmission rates than those undergoing local excision; there was no difference in overall survival between cohorts in patients with stage 1 disease; in stage 2 and 3 diseases, patients undergoing local excision and radical resection demonstrated improved rates of overall survival relative to those undergoing expectant management.

Conclusion: Expectant management is a reasonable approach for patients with stage 1 rectal neuroendocrine tumors. Local excision should be the preferred treatment option for those presenting with stage 2/3 disease.