Testing for the BRCA1 and BRCA2 Breast-Ovarian Cancer Susceptibility Genes: A Decision Analysis

Objective. The authors developed a Markov decision model to evaluate the health implications of testing for mutations in the BRCA1 and BRCA2 breast-ovarian cancer susceptibility genes. Prophylactic measures considered included various combinations of immediate and delayed bilateral mastectomy and oophorectomy or taking no action. Methods. The model incorporated the likelihood of developing breast and/or ovarian cancer, survival, and quality of life. Parameter values were taken from public data bases, the published literature, and a survey of cancer experts. Outcomes considered were additional life expectancy and quality-adjusted life years (QALYs). Results are reported for 30-year-old cancer-free women at various levels of hereditary risk. Results and conclusions. The vast majority of women will not benefit from testing because their pre-test risks are low and surgical prophylaxis is undesirable. However, women who have family histories of early breast and/or ovarian cancer may gain up to 2 QALYs by allowing genetic testing to inform their decisions. Key words: BRCA1; BRCA2; ge netic testing; breast cancer; ovarian cancer; decision analysis. (Med Decis Making 1998;18:365-375)