Surgical outcomes and predictors of overall survival of stage I-III appendiceal adenocarcinoma: Retrospective cohort analysis of the national cancer database

Background: This study aimed to determine predictors of overall survival (OS) after surgical treatment of stage IIII appendiceal adenocarcinoma and compare the outcomes of partial colectomy and hemicolectomy. Methods: A retrospective analysis of the U.S. National Cancer Database (NCDB) including patients who underwent surgery for stage I-III appendiceal adenocarcinoma between 2005 and 2019 was conducted. A propensityscore matched analysis was undertaken to compare the outcomes of partial and hemicolectomy and multivariate analysis was performed to determine predictive factors of OS. The main outcome was OS and its independent predictors. Results: 2607 patients (51.6 % male) with a mean age of 61.6 +/- 13.9 years were included. 61.7 % of patients underwent hemicolectomy while 31.7 % underwent partial colectomy. After matching, partial colectomy, and hemicolectomy had similar OS (117.3 vs 117.2 months; p = 0.08), positive resection margins, short-term mortality, and 30-day readmission. The hemicolectomy group was associated with more examined lymph nodes and longer hospital stays. Older age (HR: 1.047, p < 0.0001), rural residence area (HR: 3.6, p = 0.025), higher Charlson score (HR: 1.6, p = 0.016), signet-ring cell carcinoma (HR: 2.37, p = 0.009), adjuvant systemic treatment (HR: 1.55, p = 0.015), positive surgical margins (HR: 1.83, p = 0.017), positive lymph nodes number (HR: 1.09, p < 0.0001), and examined lymph nodes number (HR: 0.962, p = 0.001) were independent predictors of OS. Conclusions: Partial colectomy and hemicolectomy had similar OS and clinical outcomes. Older age, rural residence, higher Charlson score, signet-ring pathology, adjuvant systemic treatment, positive surgical margins, positive lymph node number, and examined lymph node number were independent predictors of OS.