Clinical value of right hemicolectomy for appendiceal carcinoids using pathologic criteria

Background: Appendiceal carcinoids (AC) are usually adequately treated by appendectomy. The European Neuroendocrine Tumours Society (ENETS) has recently reconsidered the previous pathologic criteria to identify patients at high risk of extra-appendiceal disease, who are thought to require right hemicolectomy (RHC). Aim: The aim of this retrospective, observational study was to evaluate previous and currently introduced criteria, in identifying patients with AC in whom RHC is justified. Subjects and methods: Twelve patients who underwent RHC for AC were retrospectively identified. Demographic and follow-up data were collected and appendectomy specimens were reviewed for the presence of indications leading to RHC defined as: tumor diameter ≥2 cm, tumor location at the base, mesoappendiceal extension, mitotic index Ki-67≥2%. RHC specimens were examined to identify evidence of extra-appendiceal disease, remaining and/or metastatic disease. Results: Four patients fulfilled two criteria and 8 one criterion for RHC. Two patients had tumors ≥2.0 cm, 5 located at the base, 8 invading the mesoappendix and periappendiceal fat; Ki-67 PI was 1% in all cases measured except one, in which it was 3%. Post-RHC, 3 patients (25%) had extra-appendiceal disease (no residual disease was identified in surgical margins); 1 had tumor at the colon specimen and 2 had lymph node metastasis. All 3 patients fulfilled only one pathologic criterion; 1 had tumor mesoappendiceal extension and 2 tumor location at the base of the appendix. Conclusions: Applying previous and currently introduced pathologic criteria, 25% of high-risk patients with AC had identifiable extra-appendiceal disease following RHC that might be not detected following the recently introduced ENETS criteria.