Surgical Extent and Long-term Survival in Appendiceal Adenocarcinoma: A Systematic Review and Meta-analysis

Appendiceal adenocarcinomas are rare tumours with aggressive traits, most often diagnosed incidentally after routine appendectomy. Survival rates vary greatly between the different subgroups, and adenocarcinoma has the worst prognosis. Surgery is the only curative treatment, however, the long-term benefit of extended surgical resections over appendectomy has not been established. This study aimed to investigate survival outcomes in patients with appendiceal adenocarcinoma that undergo appendectomy versus right hemicolectomy (RHC).

This study involved a systematic literature search in databases PubMed, Embase and Cochrane Library using the COVIDENCE software. Cohort studies reporting survival outcomes for patients with non-metastasised appendiceal adenocarcinoma undergoing appendectomy versus RHC were included. A random-effects model was used to pool hazard ratios (HRs) in the meta-analysis performed in Review Manager. The ROBINS-I V2 tool was used for risk of bias assessment.

A total of nine retrospective registry-based cohort studies were identified. Seven studies, with a total of 17,802 patients, reported overall survival (OS) from multivariable Cox- regression analysis. The pooled effect of adjusted HRs demonstrated increased OS [random-effects HR=0.69, 95% confidence interval (CI)=0.58-0.83] for patients undergoing RHC, with similar results in the sensitivity analysis excluding potential overlapping data (random-effects HR=0.70, 95% CI=0.51-0.96). No significant difference in OS was found in studies reporting subgroup analysis for well-differentiated adenocarcinoma.

This systematic review highlights the complexity of surgical treatment guidelines in appendiceal adenocarcinoma. The findings suggest a survival advantage for RHC compared to appendectomy. In well differentiated early-stage adenocarcinoma, appendectomy may be sufficient, although this may not apply to all subgroups.