A nationwide database study on colectomy and colorectal cancer in ulcerative colitis: what is the role of appendectomy?

AIM Although it is suggested that an appendectomy has a positive effect on the disease course in patients with ulcerative colitis (UC), recent studies indicate a potential increased risk of colectomy and colorectal cancer (CRC). This study aimed to evaluate colectomy and CRC rate after appendectomy in UC patients using a nationwide prospective database (ICC PSI-IBD database). METHOD All UC patients were retrieved from the ICC PSI-IBD database between Jan 2007 and May 2018. Primary outcomes were colectomy and CRC. Outcomes were compared in patients with and without appendectomy, with a separate analysis for timing of appendectomy (before or after UC diagnosis). RESULTS In total, 826 UC patients (54.7% female, median age 46 years (range 18-89)) were included. Sixty-three (7.6%) patients previously underwent an appendectomy: 24 (38.1%) before and 33 (52.4%) after diagnosing UC. In multivariate analysis, appendectomy after UC diagnosis was associated with a significantly lower colectomy rate compared to no appendectomy (HR 0.16, 95% CI 0.04-0.66; P=0.011), and the same non-significant trend was seen in patients with an appendectomy before UC diagnosis (HR 0.35, 95% CI 0.08-1.41; P=0.138). Appendectomy was associated with delayed colectomy, particularly when performed after diagnosing UC (P=0.009). No significant differences were found in CRC rate between patients with and without appendectomy (1.6% versus 1.2%; P=0.555). CONCLUSIONS Appendectomy in established UC is associated with an 84% decreased colectomy risk and a delay in surgery. Since the colon is in situ longer, the risk of developing CRC remains, which underscores the importance of endoscopic surveillance programs.