Cambridge Journals Online

A DECISION MODEL AND COST-EFFECTIVENESS ANALYSIS OF COLORECTAL CANCER SCREENING AND SURVEILLANCE GUIDELINES FOR AVERAGE-RISK ADULTS

Abstract

Objectives: Guidelines for colorectal cancer screening and surveillance in people at average risk and at increased risk have recently been published by the American Gastroenterological Association. The guidelines for the population at average risk were evaluated using cost-effectiveness analyses.

Methods: Since colorectal cancers primarily arise from precancerous adenomas, a state transition model of disease progression from adenomatous polyps was developed. Rather than assuming that polyps turn to cancer after a fixed interval (dwell time), such transitions were modeled to occur as an exponential function of the age of the polyps. Screening strategies included periodic fecal occult blood test, flexible sigmoidoscopy, double-contrast barium enema, and colonoscopy. Screening costs in 1994 dollars were estimated using Medicare and private claims data, and clinical parameters were based upon published studies.

Results: Cost per life-year saved was $12,636 for flexible sigmoidoscopy every 5 years and $14,394 for annual fecal occult blood testing. The assumption made for polyp dwell time critically affected the attractiveness of alternative screening strategies.

Conclusions: Sigmoidoscopy every 5 years and annual fecal blood testing were the two most cost-effective strategies, but with low compliance, occult blood testing was less cost-effective. Lowering colonoscopy costs greatly improved the cost-effectiveness of colonoscopy every 10 years.

Footnotes

¹ The authors gratefully acknowledge the contributions of Francis D. Chesley, MD, in reviewing this study and identifying necessary clinical parameters, James P. Summe in developing the database used, William Yu in commenting upon the model and reviewing the manuscript, and Kathleen A. Weis, DrPH, MSN, RN, ENP-C, PhD, for case definition and review and comment upon the model.The study was conducted under Contract No. 282-95-2002 from the former Agency for Health Care Policy and Research. An unpublished report from Health Economics Research, Inc., to the Agency for Health Care Policy and Research served as the basis for this paper. This report includes all of the decision trees, a complete list of the ranges of values for sensitivity analyses, and the Physicians' Current Procedural Terminology (CPT) and International Classification of Diseases—9th Edition—Clinical Modification (ICD-9-CM) codes used in arriving at cost estimates.Single copies of this report are available upon written request to William B. Baine, MD, Center for Outcomes and Effectiveness Research, Agency for Healthcare Research and Quality, Suite 300, 6010 Executive Boulevard, Rockville, MD 20852-3813, USA. An earlier version of this paper was presented at the Workshop on Cost-Effectiveness in Health and Medicine, William H. Natcher Conference Center, National Institutes of Health, Bethesda, Maryland, November 25–26, 1996.The statements contained in this paper are solely those of the authors and do not necessarily reflect the views or opinions of the Agency for Healthcare Research and Quality.