Appendectomy Is Oncologically Equivalent to Right Hemicolectomy for Well-Differentiated T1 Appendiceal Adenocarcinoma

BACKGROUND: Right hemicolectomy is recommended for appendiceal adenocarcinoma but may not be needed for early stage disease. OBJECTIVE: This study aimed to determine whether appendectomy offers adequate oncologic outcomes for T1 appendiceal adenocarcinoma from a national cohort of patients. DESIGN: Patients with T1 appendiceal adenocarcinoma (mucinous and nonmucinous histology) treated with either a right hemicolectomy or appendectomy between 2004 and 2016 were retrieved. Multivariate Cox regression analysis was used to identify predictors of overall survival. SETTING: The study was conducted using a national cancer database. PATIENTS: A total of 320 patients (median age, 62 y; 47% women) were identified: 69 (22%) underwent an appendectomy and 251 (78%) underwent a right hemicolectomy. MAIN OUTCOME MEASURE: Overall survival was measured. RESULTS: Nonmucinous adenocarcinoma was identified in 194 (61%), whereas 126 (39%) had mucinous adenocarcinoma. Of the overall cohort, 43% had well-differentiated histology, 39% had moderately differentiated disease, and 4% had poorly differentiated tumors. The rate of lymph node metastasis was lower in well-differentiated tumors (3%) compared with moderately (10%) or poorly differentiated tumors (25%). On univariate survival analysis, right hemicolectomy was associated with improved 1-, 3-, and 5-year overall survival in patients with moderately/poorly differentiated disease (p < 0.001) but not for well-differentiated disease (p = 1.000). After adjustment, right hemicolectomy was associated with overall survival improvement for moderately/poorly differentiated T1 adenocarcinoma (HR = 0.26 [95% CI, 0.08-0.82]; p = 0.02) but not for well-differentiated disease. LIMITATIONS: This study was limited by its retrospective nature. CONCLUSIONS: The current analysis from the National Cancer Database demonstrates that appendectomy is associated with equivalent survival to right hemicolectomy for well-differentiated T1 adenocarcinoma, whereas for moderately and poorly differentiated disease, right hemicolectomy is oncologically superior to appendectomy. See Video Abstract at http://links.lww.com/DCR/B689.

Automated summary

This study analyzed data from a national cancer database to compare the oncologic outcomes of appendectomy and right hemicolectomy for T1 appendiceal adenocarcinoma. The results showed that appendectomy is equivalent to right hemicolectomy in terms of survival for well-differentiated T1 adenocarcinoma, but right hemicolectomy is superior for moderately and poorly differentiated disease.