ASSESSMENT OF DYSPLASIA, MUCOSAL MUCINS, P53 PROTEIN EXPRESSION, AND DNA CONTENT IN ULCERATIVE-COLITIS PATIENTS WITH COLECTOMY AND ILEORECTAL ANASTOMOSIS

Background: Patients with ileorectal anastomosis after colectomy for u lcerative colitis remain at risk of developing rectal malignancy. Dete ction of mucosal dysplasia has been used for regular screening but is difficult in inflammatory mucosa, prompting the search for complementa ry markers. Methods: This prospective study aimed to assess the preval ence of dysplasia, the predominance of sialomucin, DNA aneuploidy, and p53 overexpression as possible predictors of colorectal tumourigenesi s, in the rectal mucosa of an unselected group of 27 patients with ile orectal anastomosis performed for ulcerative colitis. Patients had nei ther neoplastic nor dysplastic lesions on the colectomy specimen and t he retained rectum at the time of surgery. One biopsy specimen of each lateral rectal wall was studied, using routine histology, mucin histo chemistry, DNA flow cytometry, and the streptavidin-biotin complex met hod with D07 monoclonal antibodies directed towards the p53 protein. R esults: Seventeen, seven, and three patients showed inflammatory lesio ns of inactive, moderate, and severe active colitis, respectively. Dys plasia, sialomucin predominance, DNA aneuploidy, and p53 overexpressio n were not detected. Conclusions: The risk of malignant transformation of the rectal mucosa after ileorectal anastomosis seemed to be low in this ulcerative colitis group without high-grade dysplasia or carcino ma in the previous colectomy specimen, carefully followed up endoscopi cally and histologically. It remains to be evaluated which of the meth ods studied above will optimize the histopathologic surveillance of th e rectal mucosa of ulcerative colitis patients with ileorectal anastom osis.