A new risk assessment system called Boadicea, developed by Cambridge and funded by Cancer Research UK identified eight times as many women in the age group who would develop breast cancer in comparison to current guidelines

Breast cancer checks are missing 95% women under 50 who are at risk.

Women over 50 are offered routine mammogram checks to check their breasts for cancer. But under the current guidelines set by the National Institute of Health and Care Excellence (NICE), checks focus on inherited genes and do not consider other factors, such as lifestyle, meaning women under 50 tend to not be considered for a breast screening unless they have a strong family history of the disease.

A new risk assessment system developed by Cambridge and funded by Cancer Research UK, called Boadicea, which combines factors such as family history, lifestyle, reproductive history and genetic information identified eight times as many women in the age group who would develop breast cancer in comparison to the current guidelines

The NICE criteria is used to decide who can be referred for further breast cancer risk assessment and specialist care, but was failing to spot the majority of women under 50 who will go on to develop the disease in the next 10 years, sparking calls for a review of the criteria.

Breast cancer is the most common type of cancer worldwide and accounts for about one in four cases of cancer and is a leading cause of deaths in women under 50. in the UK. About one in seven women develop breast cancer in their lifetime, with only 5-10% of cases are linked to inherited genes and 73% of women under 50 who develop breast cancer have no family history of breast cancer.

Yet the criteria given to GPs in England to refer women miss up to 95% of patients under 50 who could develop the disease within a decade and 95% of women aged under 50 with a higher than average risk, the analysis suggest. Experts believe spotting those at the highest risk earlier would give doctors a better chance at treating or even preventing breast cancer.

Dr Juliet Usher-Smith, of the University of Cambridge, said: “We need to get better at identifying women at highest risk of breast cancer so that we can intervene early, when there are more options for treating, or even preventing, their disease.

“The current NICE criteria used in general practice are missing up to 95% of women under 50 who will go on to develop breast cancer. It’s time to look again at these criteria in the light of our findings.”

Prof Montserrat García-Closas, of the ICR, said: “There will be a balance to strike: the NICE criteria are much easier to implement, but miss a large proportion of women at elevated risk. But a full risk assessment including genetic testing will place a heavy burden on resources.

“Ultimately, it will be a trade-off between the practical, resource, and cost implications of data collection and risk assessment, and the potential benefits and harms associated with accurate and inaccurate classification of women.”

Dr Simon Vincent, chief scientific officer at Breast Cancer Now, who supported the study said: “These findings highlight the limitations of NICE's current referral criteria, and so this research must now be carefully considered as part of the current review of its family history guidelines.

“However, it’s equally important that any changes come with the needed investment in family history services, so they can be implemented effectively and fairly across the NHS.”

A NICE spokesperson said: “Nice welcomes the findings of this study and recognises the potential of multifactorial risk models in improving the identification of women at increased risk of breast cancer in the future.

“However, the current evidence does not warrant a change to our existing familial breast cancer guideline at this time. Nice remains committed to reviewing new evidence and will consider further updates as more data on feasibility and clinical outcomes become available.”