Clinical value of right hemicolectomy for appendiceal carcinoids using pathologic criteria

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).

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.

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.

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.

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.