The following is the summary of “Appendectomy Is Oncologically Equivalent to Right Hemicolectomy for Well-Differentiated T1 Appendiceal Adenocarcinoma” published in the January 2023 issue of Diseases of the Colon & Rectum by AlMasri, et al. 

Appendiceal adenocarcinoma is associated with a right hemicolectomy, albeit this procedure may not be necessary for the early stages of the disease. The purpose of this study was to assess, from a nationwide cohort of patients, whether or not oncologic results following appendectomy are sufficient for T1 appendiceal adenocarcinoma.  Between 2004 and 2016, patients with T1 appendiceal adenocarcinoma (mucinous and nonmucinous histology) were retrieved who were treated with right hemicolectomy or appendectomy. Predictors of survival were identified using a multivariate Cox regression model.

The investigation was placed within the context of a national cancer database. Out of a Whole of 320 Patients, 69 (22%) had their appendix removed, and 251 (78%) had their right hemicolectomy performed (median age, 62 years; 47% female). The primary outcome was overall survival. The results showed that 194 cases (61%) were classified as nonmucinous adenocarcinoma and 126 cases (39%) as mucinous adenocarcinoma. Overall, 43% of the group had highly differentiated tumors, 39% had moderately differentiated diseases, and 4% had poorly differentiated cancers. Low lymph node metastasis rates were seen in well-differentiated tumors (3%) compared to moderately (10%) or poorly differentiated (25%). In patients with moderately/poorly differentiated disease, right hemicolectomy was linked with better 1-, 3-, and 5-year overall survival on univariate survival analysis (P<0.001) but not for well-differentiated disease (P=1.000). 

Overall survival improved after adjustment for moderately/poorly differentiated T1 adenocarcinoma patients who underwent right hemicolectomy (HR=0.26 [95% CI, 0.08-0.82]; P=0.02), but not for patients with well-differentiated cancer. The retrospective aspect of this study is a significant limitation.  The current analysis of the National Cancer Database shows that appendectomy is associated with survival no worse than right hemicolectomy for well-differentiated T1 adenocarcinoma, while right hemicolectomy is oncologically superior to appendectomy for moderately and poorly differentiated disease.