If every woman over 30 was offered a test for cancer-causing genes, tens of thousands of ovarian and breast cancer cases could be prevented.

London researchers have calculated that if less than three-quarters of women took up the £175 test, up to 17,000 ovarian cancers and 64,000 breast cancers wouldn’t happen.

The research was carried out by a team from Barts Cancer Institute at Queen Mary University of London supported by the London School of Hygiene & Tropical Medicine.

The genes that cause most inherited ovarian and breast cancers are mutations of BRCA1 and BRCA2. In 2013, the actress Angelina Jolie announced that she’d had a double mastectomy based on family history and a positive BRCA test.

Women carrying either BRCA1 or BRCA2 gene mutations have a 17 to 44% chance of developing ovarian cancer and a 69 to 72% chance of developing breast cancer. Compare that to women without the gene ­mutations who have a 2% risk of ovarian cancer and 12% breast cancer risk.

Each year in the UK about 7,400 ovarian and 55,000 breast cancers are diagnosed.

At present, women who develop cancer and their female relatives may be offered an assessment of their family history to determine their risk of having these dangerous genes.

They are only offered genetic testing if it’s 10% or more. But according to Ranjit Manchanda, consultant ­gynaecological oncologist at Barts, this approach is imperfect.

“Almost half of the people who are a risk will not give you the family history that fit the criteria. They will be missed. So why shouldn’t we offer it to everybody?” he said.

“Genomics is coming into ­healthcare in a big way. Population testing is a way forward – we could maximise its potential for cancer prevention.”

Researchers calculate screening all women over 30 would be more efficient than the existing strategy and would be cost-effective.

Dr Manchanda said: “This could prevent thousands more breast and ovarian cancers than any current strategy, saving many lives.”

Anne Mackie, director of programmes for the UK national screening committee, said that it would “look at the results of this new research with interest”.

So why don’t we adopt this new approach? Experts say further research into acceptability and feasibility would be needed before it could be rolled out.

Gareth Evans, professor of clinical genetics at Prevent Breast Cancer, said: “I would wholeheartedly support this research being taken to the next stage, provided that public health chiefs examine how women would consent to such tests.”

Well, let’s get on with it!