Incidence of Colonic Neoplasia in Patients with a Family History of Colorectal Cancer

Abstract

Purpose: In 2005 we reported the incidence of colonic neoplasia in patients of average risk undergoing their first colonoscopy. We found that 24.2% had adenomas and 15.8% had hyperplastic polyps. Only 0.23% were diagnosed with cancer. The intent of this study was to determine the incidence of neoplasia in patients with a family history of colorectal cancer (CRC). Methods: This study was a retrospective chart review of patients undergoing their initial colonoscopy that have a family history of CRC. The primary objective was to determine the incidence of colorectal neoplasia in patients with a first degree relative with CRC. The secondary objective was to determine the incidence of neoplasia in patients with a second degree relative with CRC. All patients had a complete colonoscopy by one of the authors and all histology was reviewed by a single division of gastrointestinal pathologists. Results: 432 patient charts were available for review from a 4 year period. 254 patients were female and 178 male. The mean age was 57.2 years. 377 had first degree relatives with CRC and 55 had second degree relatives. Of the first degree patients 180 (47.75%) had one or more adenomas. 57 (15.12%) had hyperplastic polyps and 4 had CRC (1.06%). In patients with second degree relatives, 22 (40%) had one or more adenomas and 5 (9.09%) had hyperplastic polyps. None had CRC. Conclusion: 1. Patients with first degree family members having CRC are at a significant risk for having adenomas. The rate of 47.75% is nearly twice that found in average risk patients (24.2%). 2. The incidence of hyperplastic polyps is essentially the same between the first degree family group (15.12%) and the average-risk population (15.8%). 3. Though the numbers of second degree patients were low, this data suggest they also are at an increased risk (40% vs. 24.2%) compared to the average-risk population. 4. These findings should serve as an excellent educational tool in counseling patients about CRC screening with a positive family history.