Background: Appendiceal neuroendocrine neoplasms (ANEN) are uncommon entities, which run mostly an indolent course. Appendicectomy alone is usually curative, except for in a selected group of patients that are deemed to be at risk of loco-regional metastases, in whom a completion right hemicolectomy (RHC) is recommended. The current "Guidelines" criteria for the latter have been controversial, and may result in overtreatment, which is concerning for a young patient population.
Objective: The aim of this study is to evaluate the prognostic value of the current criteria in identifying more accurately those at-risk patients.
Methods: This was a retrospective study of the 263 cases of ANEN referred for advice or management to a tertiary referral unit over a 10-year period. Seventy-two patients underwent RHC, based on criteria, suggested by International Guidelines. Each one of those was assessed to identify whether it correlated with lymph node invasion (LNI) at the RHC surgical specimen.
Results: Tumour grade (p < 0.001), vascular (p = 0.044) and lymph vessel invasion (p < 0.001) were all found to be statistically significant independent risk factors for LNI identified following RHC, whilst tumour size (p = 0.375) and mesoappendiceal invasion (MAI) (p = 0.317) were not statistically significant. However, deep MAI and tumour size >2 cm showed a correlation with each other on LNI positive subgroup analysis. Location in appendiceal base made LNI more likely but again was not significant (p = 0.133).
Conclusions: Higher tumour grade and lymphovascular invasion should be considered as the most important risk prognosticators. Surprisingly, tumour size was not found to be significant in our cohort. Further international multicentre studies with large numbers of patients are needed to fully validate those data.
Keywords: Appendiceal neuroendocrine neoplasms; Appendicectomy; Appendix; Carcinoid; Lymph node invasion; Neuroendocrine tumours; Right hemicolectomy.
© 2019 S. Karger AG, Basel.