Predicting polyposis severity by proctoscopy - How reliable is it?

PURPOSE: Patients with familial adenomatous polyposis need prophylactic col ectomy and ileorectal anastomosis or restorative proctocolectomy. Preoperat ive rectal polyp counts have been used as one factor to determine which ope ration should be done, triaging patients according to risk of rectal cancer or completion proctectomy after ileorectal anastomosis. This study was des igned to examine the reliability of preoperative proctoscopy in predicting familial adenomatous polyposis severity and outcome after ileorectal anasto mosis. METHODS: Familial adenomatous polyposis patients were categorized ac cording to preoperative proctoscopy as follows: Group 1, 5 or fewer adenoma s; Group 2, 6 to 19 adenomas; Group 3, 20 or more adenomas. Familial adenom atous polyposis severity was defined as mild if there were < 1,000 polyps i n the colon at colectomy and severe if there were > 1,000 polyps. RESULTS: A total of 213 patients were reviewed, 80 in Group 1, 59 in Group 2, and 74 in Group 3. There was no difference among the groups in mean age at presen tation. Patients with fewer than five rectal adenomas were predominately fe males. They rarely had symptoms (22.8 percent), had mostly mild polyposis ( 86.5 percent), and in 74 of 80 cases underwent ileorectal anastomosis. Only six underwent restorative proctocolectomy. Of those having an ileorectal a nastomosis, five needed later proctectomy, none for cancer. Patients with 6 to 19 rectal polyps were a similar group to those with 5 or fewer. Most we re asymptomatic (67.8 percent), most had mild polyposis (81.6 percent), and 54 of 59 underwent ileorectal anastomosis (5 had restorative proctocolecto my). Only 3 of the 54 having ileorectal anastomosis needed subsequent proct ectomy, 2 for rectal cancer. The patients with 20 or more rectal polyps wer e different. They usually presented with symptoms (86 percent), the majorit y (56.6 percent) had severe polyposis, and only 50 percent (37/74) underwen t ileorectal. anastomosis, the other half having restorative proctocolectom y. Of the 37 patients with an ileorectal anastomosis, 13 needed later proct ectomy (35.1 percent), 4 for cancer (10.8 percent). CONCLUSION: Fewer than five rectal adenomas at presentation almost always predicts mild disease, a nd patients do well after ileorectal anastomosis. Twenty or more adenomas u sually means severe disease. Patients with 6 to 19 adenomas are often mildl y affected, but their phenotype is less benign than that of patients with f ewer than five polyps. Although not foolproof, proctoscopy is a useful test in triaging patients with familial adenomatous polyposis according to dise ase severity.