Surgical outcomes of appendiceal mucinous neoplasms: A systematic review and meta-analysis

Appendiceal mucinous neoplasms are rare tumors with heterogeneous pathology, typically treated with appendectomy, cecectomy, right hemicolectomy, or cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). Survival outcomes across surgical approaches remain unclear. We evaluated the outcomes of all surgical interventions for appendiceal mucinous neoplasms.

Eligible randomized controlled trials and cohort studies were retrieved from Cochrane, PubMed, Embase, and Scopus to August, 2026. Outcomes included overall and disease-free survival, recurrence, lymph-node positivity, and postoperative complications. Random-effects models were used to pool estimates. Certainty was appraised with GRADE.

The review included 43 observational cohort studies involving 12,014 patients. In localized appendiceal mucinous neoplasms, recurrence was 1.4% after appendectomy and 2.3% after right hemicolectomy. In pseudomyxoma peritonei with CRS + HIPEC, 30- and 90-day mortality was 1.8% and 1.8%. Five-year overall survival was 94.2%, 78.1%, and 47.4% for acellular mucin, low-grade, and high-grade cohorts; 5-year disease-free survival was 92.8%, 56.9%, and 30%. High-grade disease was associated with worse overall survival (hazard ratio (HR), 3.19; 95% confidence interval (CI), 1.88-5.41) and disease-free survival (HR, 3.06; 95% CI, 1.68-5.58). Incomplete cytoreduction was associated with worse overall survival (HR, 3.39; 95% CI, 1.54-7.45).

In localized appendiceal mucinous neoplasms, recurrence after resection is low; nodal involvement is uncommon in low-grade lesions but more frequently observed in mucinous adenocarcinoma. In pseudomyxoma peritonei, long-term survival after CRS + HIPEC varies by histologic grade and cytoreductive completeness. These factors may inform counseling, operative planning, and surveillance, but findings require cautious interpretation given low or very low certainty.