Evaluation of radical surgical treatment in the management of 58 locally advanced rectal neuroendocrine neoplasms, one multicenter retrospective study

Background: Locally advanced rectal neuroendocrine neoplasms (NENs) are rare, and the therapeutic effects of surgery in improving the prognosis have been questioned in previous reports.

Materials and methods: The research included 58 consecutive patients with locally advanced rectal NENs from three Chinese medical centers between 2000 and 2020. All have received radical surgical treatment. The clinicopathological and survival data were collected. Kaplan-Meier methods and a Cox proportional hazards regression model were used to evaluate the prognosis and identify independent prognostic factors.

Results: All patients were followed up for a median period of 36 (2-125) months. Of the 58 patients, 13 (22.4%) had G1 neuroendocrine tumors (NETs), 15 (25.9%) had G2 NETs, 6 (10.3%) had G3 NETs, and the remaining 24 (41.4%) patients had G3 neuroendocrine carcinomas (NECs). The 1-year and 3-year disease-free survival (DFS) rates were 64.5% and 48.8%, respectively. The 1-year and 3-year overall survival (OS) rates were 90.5% and 75.4%, respectively. Univariate analysis demonstrated that tumor differentiation (p = 0.002), gross morphology (p = 0.009), T stage (p = 0.024), and extramural vascular invasion (p = 0.009) were associated with the OS. The subsequent multivariate analysis confirmed that tumor differentiation [hazard ratio (HR) = 6.002, 95% confidence interval (CI): 1.210-29.767, p = 0.028] and gross morphology (HR = 3.438, 95% CI: 1.038-11.382, p = 0.043) were independent prognostic factors affecting the clinical outcomes.

Conclusions: Rectal NENs are a heterogeneous group of diseases. The survival benefits obtained from surgery vary widely based on the tumor clinicopathological features. Patients with G3 NECs and ulcerative mass are at high risks of poor prognosis.