Strategies to Identify the Lynch Syndrome Among Patients With Colorectal Cancer
Authors: Uri Ladabaum, Grace Wang, Jonathan Terdiman, Amie Blanco, Miriam Kuppermann, C. Richard Boland, James Ford, Elena Elkin, Kathryn A. Phillips
Journal: Annals of Internal Medicine (2011)

Background: Testing has been advocated for all persons with newly diagnosed colorectal cancer to identify families with the Lynch syndrome, an autosomal dominant cancer-predisposition syndrome that is a paradigm for personalized medicine. Objective: To estimate the effectiveness and cost-effectiveness of strategies to identify the Lynch syndrome, with attention to sex, age at screening, and differential effects for probands and relatives. Design: Markov model that incorporated risk for colorectal, endometrial, and ovarian cancers. Data Sources: Published literature. Target Population: All persons with newly diagnosed colorectal cancer and their relatives. Time Horizon: Lifetime. Perspective: Third-party payer. Intervention: Strategies based on clinical criteria, prediction algorithms, tumor testing, or up-front germline mutation testing, followed by tailored screening and risk-reducing surgery. Outcome Measures: Life-years, cancer cases and deaths, costs, and incremental cost-effectiveness ratios. Results of Base-Case Analysis: The benefit of all strategies accrued primarily to relatives with a mutation associated with the Lynch syndrome, particularly women, whose life expectancy could increase by approximately 4 years with hysterectomy and salpingo-oophorectomy and adherence to colorectal cancer screening recommendations. At current rates of germline testing, screening, and prophylactic surgery, the strategies reduced deaths from colorectal cancer by 7% to 42% and deaths from endometrial and ovarian cancer by 1% to 6%. Among tumor-testing strategies, immunohistochemistry followed by BRAF mutation testing was preferred, with an incremental cost-effectiveness ratio of $36 200 per life-year gained. Results of Sensitivity Analysis: The number of relatives tested per proband was a critical determinant of both effectiveness and cost-effectiveness, with testing of 3 to 4 relatives required for most strategies to meet a threshold of $50 000 per life-year gained. Immunohistochemistry followed by BRAF mutation testing was preferred in 59% of iterations in probabilistic sensitivity analysis at a threshold of $100 000 per life-year gained. Screening for the Lynch syndrome with immunohistochemistry followed by BRAF mutation testing only up to age 70 years cost $44 000 per incremental life-year gained compared with screening only up to age 60 years, and screening without an upper age limit cost $88 700 per incremental life-year gained compared with screening only up to age 70 years. Limitation: Other types of cancer, uncertain family pedigrees, and genetic variants of unknown significance were not considered. Conclusion: Widespread colorectal tumor testing to identify families with the Lynch syndrome could yield substantial benefits at acceptable costs, particularly for women with a mutation associated with the Lynch syndrome who begin regular screening and have risk-reducing surgery. The cost-effectiveness of such testing depends on the participation rate among relatives at risk for the Lynch syndrome. Primary Funding Source: National Institutes of Health.