Too many women are getting unnecessary mastectomies and other invasive procedures because of a knowledge gap about differences in cancer genes. A new study offers a path to closing the gap.
Nearly a decade ago, Angelina Jolie made famous that preventative mastectomies can help women with BRCA gene mutations — changes that alter gene function. These women may have more than four times higher than normal chances of getting breast cancer. Mutations in BRCA genes can also increase risks for ovarian, pancreatic, and prostate cancer.
Far fewer headlines covered the fact that around 40% of changes to the BRCA1 and BRCA2 genes are a black box. Are these gene variants harmful, harmless, or somewhere in between? Scientists don't fully know — and that carries consequences.
"The evidence is that people with variants of uncertain significance are overtreated, because people just see it as a bit of a red flag and can't help thinking it must be important," said Amanda Spurdle, a cancer epidemiologist at QIMR Berghofer Medical Research Institute near Brisbane, Australia.
A 2017 study found up to half of surgeons prescribed the same treatment whether a BRCA variant was uncertain or known to cause disease. Women with uncertain variants commonly underwent double mastectomies, a painful procedure with serious risks. Other cancer treatments, like ovary removals, may prevent people from having children. (People of all genders may be tested and treated for BRCA gene mutations.)
Even just receiving genetic test results indicating "variant of uncertain significance" can lead to anxiety in both patients and their clinicians.
Researchers have the tools to crack which variants are harmful or harmless. But they lack the raw materials, which are locked away in highly-protected databases of people's genomes and medical records.
