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* = Presenting author

P468 Appendectomy is associated with an increased risk of colonic neoplasia in Ulcerative Colitis

Y. Harnoy*1, Y. Bouhnik2, V. Desfourneaux1, L. Maggiori3, L. Sulpice1, B. Larroque4, D. Cazals-Hatem5, K. Boudjema1, Y. Panis3, E. Ogier-Denis6, X. Treton2

1Hopital Pontchaillou, CHU de Rennes, Service de Chirurgie Hépatobiliaire et Digestive, SCHBD, Rennes, France, 2Hôpital Beaujon, Gastroentérologie, MICI et Assistance Nutritive, Clichy, France, 3Université Paris Diderot Hôpital Beaujon - APHP, Service de Chirurgie Colo-rectale, Clichy, France, 4Université Paris Diderot Hôpital Beaujon - APHP, Département de la recherche Clinique, Clichy, France, 5Université Paris Diderot Hôpital Beaujon - APHP, Département d'anatomopathologie, Clichy, France, 6INSERM, UMRS1149, Team «Physiopathology of Inflammatory Bowel Diseases», Centre de Recherche Bichat Beaujon, Paris, France

Background

Appendectomy is usually considered as a protective factor of ulcerative colitis (UC). Currently clinical trials are testing appendectomy to treat UC. Original results of experiments performed in a murine model of UC-like colitis (IL10/Nox1 mice) showed that appendectomies provoked an un-expected high rate of early colonic neoplasia. The purpose of this study was to determine if previous appendectomy in patients with UC was associated with high risk of colonic neoplasia.

Methods

This is a retrospective study including all the consecutive UC patients who required colectomy in two French referral university centers between 2001 and 2011. Medical records and colon specimens of the 232 consecutive UC patients were analyzed. UC features and previous appendectomy were retrospectively collected. Presence of the appendix, high-grade dysplasia or colon cancer, and colitis severity on the surgical specimens of colectomy were assessed blindly by gastro-intestinal pathologists.

Results

Among 232 UC patients who underwent colectomy, 15 had previous appendectomy and 39 had colonic high grade dysplasia (HGD) or cancer. Among patients with previous appendectomy 5 had colon cancer (33%) and 4 HGD (27%) versus 12 with colon cancer (5.5%) and 18 with HGD (8.3%) in the non-appendectomy group. Previous appendectomy was the highest independent risk factor of colorectal neoplasia in UC [p=0.005, OR=17.16 (CI 3.5-84.2)]. Primary sclerosing cholangitis, already identified as a risk factor of colonic neoplasia in UC subjects was also found [p=0.002, OR=4.46 (CI 1.7-11.6)].

Conclusion

Murine data on a new model of UC-like colitis showed that appendectomy, for a non-inflamed appendix, triggered colonic carcinogenesis. Our study identified previous appendectomy as a strong independent risk factor of colonic neoplasia in UC patients. We recommend: 1- to stop current clinical trials testing appendectomy as a treatment for UC, as long as larger data on this risk are not available, and 2- to screen carefully UC patients with previous appendectomy.