Almost 6,000 invasive breast cancers too small to be felt by hand were picked up by the British National Health Service (NHS) screening programme last year, figures have shown.
Data from the NHS Information Centre reveals 5,913 invasive cancers measuring less than 1.5cm were found as part of England’s breast screening programme in 2009/10.
They accounted for just over two-fifths (41.6 epr cent) of all the 14,229 breast cancers detected among women aged 45 and over.
The figures come after a study published earlier this month found almost one in three breast cancers are diagnosed in between regular screenings. They are mostly picked up because the woman starts developing symptoms, such as a lump in her breast.
These ‘interval cancers’ include tumours that grow between screening appointments, as well as those that are missed or are undetectable during mammograms.
Experts behind that UK-wide study, published in the British Journal of Cancer, said reducing the length of time between mammograms could lead to more cancers being detected.
Women in the UK aged 50 and over are invited for NHS breast screening every three years. Around 1.5 million women are screened annually and the programme is currently being extended to all women aged 47 to 73.
The NHS Information Centre data showed that the percentage of small invasive cancers, as well as the total number of cancers detected, was slightly higher than in 2008/9. Some 41.3 per cent (5,850) of the 14,166 cancers detected then were invasive and measured less than 1.5cm.
Of women invited for screening, excluding those who are recalled early, stood 73.2 per cent of women aged 50 to 70 in 2009/10, compared to 73.6 per cent in 2008/9 and 74.4 per cent in 2004/05. Some 1.79 million of those aged 45 and over were screened, compared to 1.77 million the year before.
Chief executive of the NHS Information Centre, Tim Straughan, said: “This highlights the vital impact of the national screening programme in detecting breast cancers that are so small they measure less than 15mm and could have otherwise gone unnoticed.”