The American Cancer Society has recommended annual magnetic resonance imaging (MRI) as an adjunct to mammography for breast cancer screening in women who have a lifetime risk of breast cancer of approximately 25% to ?50%, as determined by models such as the Gail risk test. A new simulated clinical trial evaluated the cost-effectiveness of using 7 single-nucleotide polymorphisms (7SNPs) in combination with the Gail test to assess the cost-benefit of annual MRI screening in women at risk for breast cancer (Folse HJ, et al. Cancer Prev Res [Phila]. 2013;6:1328-1336).
“For questions of screening in particular, there is often a lack of hard clinical trial data on the benefits and costs of screening due to the high costs and long-time horizons needed for such studies,” Henry J. Folse, PhD, scientist at Evidera (previously Archimedes), told Value-Based Cancer Care.
Folse and colleagues used the Archimedes simulation model of breast cancer risk factors, disease progression, and healthcare processes to estimate the cost-effectiveness of using genetic testing to assess the risk for breast cancer in women at risk and to identify those who would benefit from MRI screening.
“Models such as the Archimedes Model serve a valuable role in that they integrate a large amount of data from many different sources, including clinical trials and observational studies, to make specific predictions that can help guideline authors make decisions based on the best available evidence,” Dr Folse said.
This model enables researchers and decision makers to make better informed decisions that could influence clinical and economic outcomes.
The Gail risk model, which is widely used by the National Cancer Institute, estimates a patient’s breast cancer risk using age, race, family history, age at menarche, first live birth, and number of biopsies. The 7SNP genetic test uses the genotype of the patient to refine the estimate of the Gail test.
“Our study shows that by identifying patients who are actually at high risk of cancer, but who were not identified by the commonly used Gail risk test, we can prevent additional cancer deaths compared with using the Gail test alone,” Dr Folse said. “Specifically, for patients with a lifetime risk of at least 10%, the model showed that the 7SNP test results in a 2.7% reduction in cancer death relative to the Gail test alone.”
Study Details Data from the Surveillance, Epidemiology, and End Results database were used for the cancer incidence. Average-risk patients (<20% risk) had an annual mammogram, and high-risk patients (>20% risk) had an annual MRI. The primary outputs of the Archimedes Model were total breast cancer deaths, total (discounted) costs, and total (discounted) quality-adjusted life-years (QALYs). The cohort consisted of 100,000 non-Hispanic white women (aged ?40 years), with no history of cancer and a lifetime Gail risk of breast cancer of at least 10%.
Cost-Effective and Quality-of-Life Benefits For patients with a lifetime breast cancer risk of at least 10%, adding the 7SNP test resulted in a 2.7% reduction in cancer deaths compared with the Gail test alone. “Furthermore, we identified a subpopulation at an intermediate risk (16%-28%) as optimally cost-effective [for MRI]. For this group, the cost per QALY was $163,264, as estimated by our model,” said Dr Folse. That is, the 7SNP test saved 0.005 QALYs per person, at a cost of $163,264 per QALY.
The cost-effectiveness of the 7SNP test for patients with intermediate Gail risk is similar to that of other recommended strategies, including the American Cancer Society guidelines that recommend annual MRI screening for patients with a lifetime risk greater than 20% or with BRCA1/BRCA2 mutations, for which the model estimated a cost of $141,415 per QALY, relative to a mammogram. The results were sensitive to the age of the patient at which the test was administered, the discount rate, and the expenditures of the genetic test and MRI, which can vary considerably.
Based on these findings, the 7SNP genetic test for breast cancer is most cost-effective when used to guide MRI screenings in patients at intermediate risk for breast cancer.
