Estimation of impact of American College of Radiology recommendations on CT colonography reporting for resection of high-risk adenoma findings.

ABSTRACT

OBJECTIVES: The American College of Radiology (ACR) recommends that polyps < or =5 mm in size not be reported on computed tomography (CT) colonography studies. Patients with 1 or 2 polyps 6-9 mm in size can be offered "CTC surveillance" in 3 years in lieu of polypectomy. The aim of the study was to determine the impact of ACR recommendations on resection of high-risk adenoma findings using an endoscopic polyp/histology database. METHODS: Excluding patients with inflammatory bowel disease (IBD) and polyposis, 10,034 patients underwent colonoscopy and 10,780 polyps were removed from 5,079 patients over a 5-year interval. High-risk adenoma findings were defined as an advanced adenoma (> or =1 cm in size, high-grade dysplasia (HGD), or villous elements) or 3 or more adenomas of any size, per postpolypectomy surveillance recommendations. RESULTS: A total of 5,079 patients (51%) had at least 1 polyp, 2,907 (29%) had at least 1 adenoma, and 1,001 (10%) had high-risk adenoma findings, of these, 293 (29%) had either 3 adenomas < or =5 mm in size (n=267) or an advanced adenoma < or =5 mm in size (or both) and no polyp of any histology > or =6 mm in size. There were 774 patients with 1 or 2 polyps 6-9 mm in size and no polyps of any histology > or =10 mm in size. Of these patients 184 (18% of the patients with high-risk adenomas) had either 3 or more adenomas < or =9 mm in size (n=149) or an advanced adenoma < or =9 mm in size (or both findings). There were 2,174 patients age > or =50 years with the primary indication of screening of whom 326 (15%) had high-risk adenoma findings. Of these, 108 (33%) had either > or =3 adenomas < or =5 mm in size or an advanced adenoma < or =5 mm in size and no polyps > or =6 mm in size. An additional 75 (23%) had no polyp > or =10 mm in size, 1 or 2 polyps 6-9 mm in size and > or =3 adenomas < or =9 mm in size or an advanced adenoma < or =9 mm in size. CONCLUSIONS: If computed tomographic colonography (CTC) rather than colonoscopy were used in this population, assuming 100% sensitivity of CTC for polyps > or =6 mm and ACR interpretation recommendations, then 29% of all patients and 33% of screening patients age > or =50 years with high-risk adenoma findings would be interpreted as normal, and an additional 18-23% of these groups with high-risk adenoma findings, respectively, could have polypectomy delayed at least 3 years.