New genetic test for breast cancer shows benefits in study

A new test for a wide range of genetic risk factors for breast cancer could be an effective means of screening for the disease, according to a study.

Hundreds of research institutions, led by the Institute of Cancer Research in London and the University of Cambridge, have collaborated to trial the test – which looks for differences in 77 separate letters of DNA code with a link to breast cancer among 65,000 women.

They found a significant link between each patient's polygenic risk score and breast cancer risk. Women in the top 20 percent for polygenic risk score were 1.8 times more likely to develop breast cancer than the average person, while those in the top one percent had a threefold increase in their cancer risk.

Analysing this panel of 77 genetic markers was also shown to be much more accurate in defining risk than previous tests that used fewer markers.

Study co-leader Montserrat Garcia-Closas, professor of epidemiology at the Institute of Cancer Research, said: "This type of testing could fit alongside other standard risk measures, such as family history and body mass index, to improve our ability to target the best preventive treatments and advice to those women most likely to benefit from them."

This could represent a breakthrough in diagnosing a disease that remains the UK's most common form of cancer.