Evaluation of appendectomy as a potential risk factor for immune checkpoint inhibitor-associated enterocolitis.

Aims: The relationship between appendectomy and immune checkpoint inhibitor (ICI) enterocolitis was explored. Methods: Patients who began ICIs between July 2010 and September 2020 (n = 10,907) were included. The exposure group included patients with evidence of appendectomy prior to ICIs in operative notes (n = 380). The control group included patients with evidence of normal appendix in radiologic reports (n = 3602). ICI enterocolitis was defined as histopathologic evidence of colitis or enteritis attributed to ICIs. The association between appendectomy and ICI enterocolitis was characterized by multivariate logistic regression. Results: 248 patients (6.2%) developed ICI enterocolitis. The odds of ICI enterocolitis were similar among those with prior appendectomy and those without appendectomy (adjusted odds ratio: 0.82; 95% CI: 0.49-1.36; p = 0.449). Conclusion: No association was found between prior appendectomy and ICI enterocolitis.