[Frequency of proximal colonic extension of distal ulcerative colitis]

To evaluate the frequency of colonic extension in patients with rectal or rectosigmoidal forms of ulcerative colitis and to look for factors associated with a higher risk of proximal colonic extension.

We conduct a retrospective study on cases of ulcerative colitis limited to the rectum and the rectosigmoid followed up at least for 6 months. Colonic extension was defined by apparition of endoscopic features of ulcerative colitis in initially normal segments of the colon.

From 1984 to 2004, 70 patients with distal ulcerative colitis were studied. Initial location was the rectum in 25 cases and the rectosigmoid in 45 cases. After a mean follow-up of 49.4 months, proximal colonic extension was observed in 7 cases (10%), with an actuarial frequency of 12% at 5 years, 20% at 10 years and 20% at 20 years. Patients with colonic extension had a higher number of relapses compared to patients without extension (4.28 +/- 1.36 vs. 1,41 +/- 1.22, p = 0.001). Age, sex-ratio, initial location, maintenance therapy and diagnosis of refractory distal colitis were not associated with a higher risk of colonic extension.

Colonic extension in our population occurs during the first years after the diagnosis of distal ulcerative colitis. Patients with more relapses are at increased risk of proximal colonic extension.