Rectal neuroendocrine tumors: Can they be observed?

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.

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.

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.

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.