Knowing whether you’re a genetic carrier for a disease can be invaluable. A patient who learns she’s at heightened risk for breast cancer, for example, may opt for more frequent mammograms or have a preventative mastectomy, potentially adding many happy and healthy years to her life.
The US Preventive Services Task Force currently advises that individuals who have a family history of a disease should consider genetic testing. But taking a family approach to testing, applying one patient’s results to understand the risks to other family members, could generate comparable health benefits at less cost, suggests research by Chicago Booth’s Dan Adelman and Kanix Wang.
In theory, everyone could be tested for a wide array of potential diseases. But that’s a cost-prohibitive proposition, so what’s the optimal testing system? The researchers studied the issue by simulating the testing of 5 million people for the BRCA1 and BRCA2 genes, which are associated with an increased risk of developing breast cancer. The algorithm Adelman and Wang developed can determine who needs to be tested and can rule out the possibility that some family members are at risk on the basis of others’ results.
At $750 per test, an optimal family-testing policy involving these genes alone would add nearly 300,000 quality-adjusted life years to at-risk people over their lifetimes, 3,000 more QALYs than would be added by testing all people who meet the USPSTF’s guidelines, for $500 million less. A QALY is a measure used by economists to tally the quality and quantity of a life, and one QALY equates to a year of perfect health.
Consider a family in which two of three sibling grandchildren test positive for a BRCA gene, the third sibling tests negative, and the only other known piece of information is that the paternal grandmother had previously tested negative. According to the current guidelines, the siblings’ mother and maternal grandmother should be tested for the gene. But according to Adelman and Wang’s algorithm, it may make the most sense to test only the paternal grandfather. If he were to test negative, it would be clear that the mother and maternal grandmother are the carriers. Under current guidelines, men are rarely tested for a BRCA gene, but doing so could offer valuable information about other family members.
“One of the essential benefits of testing families is that the informational value of learning test results could outweigh the direct benefits from individual genetic testing. This value hinges on the free flow of information among family members,” Adelman and Wang say. “However, the burden of sharing still falls on individual family members. There would be even more QALYs-improving and cost-saving opportunities if future healthcare legislation were to accommodate family genetic testing, for example, by authorizing primary physicians to contact close relatives.”