Experts have developed a potentially “game-changing” test to predict a woman’s risk of breast cancer.

It combines information on family history and hundreds of genetic markers with other factors, such as weight, to give the most comprehensive assessment possible, says Cancer Research UK.

The test is not yet routinely available on the NHS – some GPs and specialists are trialling it first.

It is part of a push to spot cancers earlier through tailored screening.

Women at high risk could be given preventative treatments or offered more checks, say the researchers.

Nearly 55,000 women are diagnosed with breast cancer each year. A large proportion of the cases occur in women who have risk factors.

Prof Antonis Antoniou, lead researcher at the University of Cambridge, said: “This is the first time that anyone has combined so many elements into one breast cancer prediction tool.

“It could be a game changer for breast cancer because now we can identify large numbers of women with different levels of risk – not just women who are at high risk.

“This should help doctors to tailor the care they provide depending on their patients’ level of risk.

“For example, some women may need additional appointments with their doctor to discuss screening or prevention options and others may just need advice on their lifestyle and diet.

“We hope this means more people can be diagnosed early and survive their disease for longer but more research and trials are needed before we will fully understand how this could be used.”

The Breast Cancer Now charity called it a “promising step” but cautioned that more research was needed to develop and test the tool before it could begin to change NHS practice.

“In the meantime, we’d encourage anyone who is concerned about their breast cancer risk to speak to their GP,” spokeswoman Eluned Hughes said.

“While there are some factors that we can’t change, there are steps everyone can take to reduce their risk of breast cancer, such as exercising regularly, maintaining a healthy weight and drinking less alcohol.”

The test, which also assess ovarian cancer risk, is described in the journal Genetics in Medicine.