More than one in four women between the ages of 50 and 70 do not attend breast screening appointments, NHS figures have revealed.
The statistics show that 27% of the 2.2m women invited to an appointment last year did not attend. Experts predict that as many as 600 lives could be saved if attendance was increased.
Breast cancer is the most common form of cancer in the UK, with more than 45,000 new cases diagnosed each year and up to 12,000 people being killed.
Results from the NHS breast screening programme in England show that around 10,000 cases of cancer are diagnosed through the scheme, saving around 1,400 lives annually.
Professor Julietta Patnick, director of the NHS Breast Cancer Screening Programme, said: "The programme is working hard to understand the factors that affect women's uptake of invitations in order to provide the best possible service, and to provide women with the right information for them to make their decision."