To Örebro University

Background: Long-term outcomes, including health-related quality of life (HRQoL) issues are understudied in patients with well-differentiated ppendiceal neuroendocrine neoplasms (WD-ANENs). We aimed to evaluate the validity of currently applied criteria for completion prophylactic right hemicolectomy (pRHC) and determine its association with patient outcomes.

Methods: This cohort study included patients with WD-ANENs from five European Centers of Excellence for neuroendocrine tumors. Eligible patients were divided between those who underwent appendectomy alone and those who underwent pRHC. HRQoL EORTCqlqc30 questionnaires and cross-sectional imaging data were prospectively collected.

Results: The 166 patients included 119 women (71.2%). Mean age was 31 ± 16 years. Mean follow-up was 51 ± 54 months. Most patients (152[92%]) had tumors≤20 mm. Fifty-eight patients (34.9%) underwent pRHC that was unnecessary in 65.5%(38/58); and in 79.1%(34/43) of tumors≤20 mm. In multivariable analysis, tumor size>20 mm was the only independent predictor for lymph node (LN) positivity(p = 0.021). No disease-specific mortality was reported. Three patients developed recurrence (n = 2inthepRHC group vs. n = 1 in the appendectomy group;p = 0.263). Although global HRQol was not significantly depreciated in patients undergoing pRHC compared to appendectomy alone (median scores 0.79[0.25-1] vs. 0.83[0.08-1], respectively; p = 0.738), impaired social functioning (p = 0.016), diarrhea (p = 0.003) and financial difficulties (0.024) were more frequently reported in the pRHC group. Furthermore, physical-(p = 0.066) and role functioning (p = 0.055), as well as constipation issues(p = 0.072) emerged in the pRHC group with marginal significance.

Conclusion: pRHC in WD-ANENs comes at a high rate of unnecessary procedures, functional HRQoL issues and diarrhoea. LN positivity at pRHC may lack prognostic significance, as no disease-specific mortality and scarce recurrence was evident in this series. The validity of contemporary criteria and the value per se of pRHC to patients with WD-ANEN is challenged.