Using Risk for Advanced Proximal Colonic Neoplasia To Tailor Endoscopic Screening for Colorectal Cancer

16 December 2003 | Volume 139 Issue 12 | Pages 959-965

Background: Colonoscopic screening for colorectal cancer has been suggested because sigmoidoscopy misses nearly half of persons with advanced proximal neoplasia.

Objective: To create a clinical index to stratify risk for advanced proximal neoplasia and to identify a subgroup with very low risk in which screening sigmoidoscopy alone might suffice.

Design: Cross-sectional study.

Setting: A company-based program of screening colonoscopy for colorectal cancer.

Patients: Consecutive persons 50 years of age or older undergoing first-time screening colonoscopy between September 1995 and June 2001.

Measurements: A clinical index with 3 variables was created from information on the first 1994 persons. Points were assigned to categories of age, sex, and distal findings. Risk for advanced proximal neoplasia (defined as an adenoma 1 cm or larger or one with villous histology, severe dysplasia, or cancer) was measured for each score. The index was tested on the next 1031 persons from the same screening program.

Results: Of 1994 persons, 67 (3.4%) had advanced proximal neoplasia. A low-risk subgroup comprising 37% of the cohort had scores of 0 or 1 and a risk of 0.68% (95% CI, 0.22% to 1.57%). Among the validation group of 1031 persons, risk for advanced proximal neoplasia in the low-risk subgroup (comprising 47% of the cohort) was 0.4% (upper confidence limit of 1.49%). Application of this index detected 92% of persons with advanced proximal neoplasms and, if applied following screening sigmoidoscopy, could reduce the need for colonoscopy by 40%. The marginal benefit of colonoscopy among low-risk persons was small: To detect 7 additional persons with advanced proximal neoplasia, 1217 additional colonoscopies would be required.

Conclusions: This clinical index stratifies the risk for advanced proximal neoplasia and identifies a subgroup at very low risk. If it is validated in other cohorts or groups, the index could be used to tailor endoscopic screening for colorectal cancer.

Editors' Notes Context Screening for colorectal cancer with sigmoidoscopy alone often misses proximal neoplasia. Contribution Using data from a company-based program of screening colonoscopy, these authors developed a risk index for advanced proximal neoplasia that stratified patients on the basis of age, sex, and distal colon findings. The prevalence of proximal neoplasia was 0.4%, 1.9%, and 3.8% among low-, intermediate-, and high-risk patients, respectively, in the validation sample. Implications A risk index that includes distal findings identifies low-risk patients whose probability of advanced proximal neoplasia is 1 in 250. The index may help identify patients who do not need colonoscopy after sigmoidoscopy. Cautions The index needs validation in additional populations. –The Editors

 

Author and Article Information

From Indiana University School of Medicine, Indiana University, Roudebush Veterans Affairs Medical Center, The Regenstrief Institute, Inc., Indianapolis Gastroenterology Research Foundation, and Eli Lilly and Co., Inc., Indianapolis, Indiana; and University of North Carolina, Chapel Hill, Chapel Hill, North Carolina.

Grant Support: In part by grant K24 DK 02756 from the National Institute of Diabetes and Digestive and Kidney Disorders (Dr. Imperiale).

Potential Financial Conflicts of Interest: At the time of data collection, Mr. Wagner was responsible for the Indianapolis Gastroenterology Research Foundation portion of the Eli Lilly colorectal cancer program, and a portion of his salary was paid by funds received from Lilly for program management.

Requests for Single Reprints: Thomas F. Imperiale, MD, The Regenstrief Institute, Inc., 1050 Wishard Boulevard, Indianapolis, IN 46202.

Current Author Addresses: Dr. Imperiale: The Regenstrief Institute, Inc., 1050 Wishard Boulevard, Indianapolis, IN 46202.

Ms. Lin: 6931 Middlebranch Avenue, Canton, OH 44721.

Dr. Rogge: Indianapolis Gastroenterology Research Foundation, 8051 South Emerson 200, Indianapolis, IN 46237.

Dr. Ransohoff: CB 7080, 4103 Bioinformatics Building, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7080.

Mr. Wagner: Med Institute, 1400 Cumberland Avenue, West Lafayette, IN 47906.

Dr. Larkin: Eli Lilly and Co., Lilly Corporate Center, DC 2111, Indianapolis, IN 46285.

Author Contributions: Conception and design: T.F. Imperiale, D.R. Wagner, D.F. Ransohoff.

Analysis and interpretation of the data: T.F. Imperiale, D.R. Wagner, C.Y. Lin, D.F. Ransohoff.

Drafting of the article: T.F. Imperiale, D.F. Ransohoff.

Critical revision of the article for important intellectual content: T.F. Imperiale, D.R. Wagner, G.N. Larkin, J.D. Rogge, D.F. Ransohoff.

Final approval of the article: T.F. Imperiale, J.D. Rogge, D.F. Ransohoff.

Provision of study materials or patients: D.R. Wagner, G.N. Larkin, J.D. Rogge.

Statistical expertise: T.F. Imperiale.

Obtaining of funding: T.F. Imperiale.

Administrative, technical, or logistic support: D.R. Wagner, C.Y. Lin, G.N. Larkin.

Collection and assembly of data: T.F. Imperiale, D.R. Wagner, C.Y. Lin.