Evaluating the necessity of right hemicolectomy in high-risk appendiceal neuroendocrine tumors: a retrospective analysis.

BACKGROUND

Appendiceal neuroendocrine neoplasms (ANENs) are often incidental findings following appendectomy. The necessity of complementary right hemicolectomy (RHC) for ANENs with high-risk features (HRFs), such as tumor size over 2 cm, mesoappendiceal invasion, Ki-67 index > 10%, or positive lymphovascular invasion, remains debated. This study investigates the association between HRFs and disease-free survival (DFS) to assess the need for routine RHC in ANEN patients with HRFs.

METHODS

We retrospectively reviewed records of patients who underwent appendectomy between 2008 and 2018 and had ANENs on histopathology. High-risk features were defined based on tumor size, Ki-67 index, surgical margin status, and lymphovascular invasion. Patients with insufficient follow-up were contacted for additional imaging. Kaplan-Meier survival analysis was employed to assess DFS across different risk groups. DFS was defined as the interval between appendectomy and relapse, measured in months. Data were analyzed using descriptive statistics, and categorical variables were summarized as frequencies.

RESULTS

Thirty-four ANEN patients were identified, with 12 having no HRFs and 22 exhibiting at least one. Only three patients underwent RHC, none of whom demonstrated residual or metastatic disease on follow-up. The mean follow-up was 117.2 months, during which all patients, except one who died in an accident, remained alive and disease-free. Kaplan-Meier survival analysis showed no significant difference in DFS between patients with and without HRFs.

CONCLUSION

Routine RHC may not improve outcomes for ANENs with HRFs, as DFS remained high without additional intervention. However, given the small sample size, a multi-center study with a larger cohort is necessary to confirm these findings.