P136 Risk of polyps and colorectal cancer in patients with microscopic colitis: case-control study with long-term follow-up
Fajardo, I.(1);Zabana, Y.(1,2);Salas, A.(3);Aceituno, M.(1,2);Ruiz, L.(1,2);Esteve, M.(1,2);Fernández-Bañares, F.(1,2);
(1)Hospital Universitari Mútua de Terrassa, Gastroenterology Department, Terrassa, Spain;(2)Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas CIBEREHD, CIBERehd, Barcelona, Spain;(3)Hospital Universitari Mútua de Terrassa, Pathology Department, Terrassa, Spain;
A previous study (Fernandez-Bañares et al, UEGJ 2016;4s: A434) showed that in microscopic colitis (MC) there is a low frequency of polyps and colorectal cancer (CRC) compared to the general population at medium risk, without observing differences with a group of chronic diarrhoea and normal colonic histology. The aim of the present study is to assess whether this low incidence of adenomas in patients with MC and chronic diarrhoea persists in the long term.
Patients with follow-up colonoscopies for control of colonic polyps or for diarrhoea recurrence after index colonoscopy were included in two groups: patients in the MC group (32/100 patients, Group A) and in the chronic diarrhoea group (68/200 patients, Group B). Colonic polyps were recorded, collecting adenomas, advanced adenomas (AA; high-grade dysplasia -HGD-, villous component and size > 1cm) and CRC. A conditional logistic regression analysis was performed (COXREG: 1 case-2 controls, matched by age and sex).
With a median follow-up of 9 years (IQR =7–12 years), 2 CRC were diagnosed in Group B (2/200). A total of 44 colonoscopies were performed in Group A and 105 in Group B, with no significant differences between groups (p=0.35). Recurrent diarrhoea was present in 25% of Group A and 38% of Group B (p=0.19). In these endoscopies, the total frequency of adenomas was: Group A 28% and Group B 56% (p=0.009). The frequency of AA was: Group A 12.5% and Group B 14.7% (p=1). The frequency of HGD/CRC was 0% in Group A and 5.8% in Group B (p=0.30). For adenomas, the COXREG OR was 0.2 (CI=0.05–0.75; p=0.017) and for AA (with CRC included) 0.8 (CI 0.26–2.9; p=0.8).
After long-term follow-up, patients with MC have a decreased frequency of adenomas and a trend to have less HGD/CRC compared with patients with chronic diarrhoea and normal colonic histology. These differences, therefore, are probably due to the MC itself and not to a protective effect of diarrhoea, as had been previously suggested. These results support the recommendation of not doing specific screening for CRC prevention in patients with MC.