If you’re a woman in your 20s or 30s, you probably haven’t had a mammogram. The people who calculate the need for medical tests figure it’s not worth it to screen most women at such a relatively young age.
But if you already knew, from your genes, that you were at elevated risk for breast cancer, you might feel differently. Now, some researchers feel differently about it too.
Researchers at the University of Cambridge found that women with 14 of the genetic markers associated with increased risk of breast cancer had about six times the risk of breast cancer as women with none of the markers. They recently reported their findings in the New England Journal of Medicine.
Their research could mean a big change in the timing of cancer screening for some women, as well as the ways doctors detect early signs of the disease.
“We believe genetic testing has the potential to enable doctors to identify a woman with an increased risk of breast cancer who would benefit from mammography at an early age or women who may benefit from regular MRI scanning as well,” said lead author Dr. Paul Pharoah in a written statement.
Traditionally, doctors start screening for breast cancer when women turn 40, recommending they undergo the specialized X-ray exam once every one or two years. This approach can be harmful to some women who develop the disease in their 20s or early 30s because the cancer is more likely to go undetected for some time, allowing it to metastasize or spread. Yet cancer specialists have long thought it would be too cost prohibitive to subject the entire female population to breast cancer screening at an early age, especially when that screening would benefit such a relatively small population.
By performing genetic tests to get a better idea of a woman’s risk profile, however, doctors can personalize screening approaches and tailor lifestyle advice for those who need it most. The idea is to prevent the disease or use screening tools to catch it early, before it has spread.
Genetic profiles could someday also tell a woman whether she needs so many mammograms. “This approach would also identify a 55-year-old woman with a low chance of breast cancer who possibly wouldn’t need such regular checks,” Pharoah said.
The Cambridge study suggests that TNRC9, CASP8, FGFR2 and several other genes should be analyzed to determine breast cancer risk level. Doing this, they believe, could improve the efficiency of screening programs. The study did not endorse analysis of a smaller number of genes—the researchers noted that testing for only one of the genes is of little clinical use because of the modest relative risks conferred by a smaller number of markers. But when the genes are viewed in combination, the information is much more helpful. In this study, women with all of the breast cancer susceptibility genes had 6.3 times the risk of those who did not.
Navigenics presently tests women for the presence of all the genes in this study but one, chr8:128424800, which will be added to our service later this year.