Breast cancer screening for women aged over 70 may not dramatically reduce the numbers of those diagnosed with advanced cases of the disease, according to a new study.
Research published today in the BMJ has shown that extending screening to women aged 69-75 could instead lead to ‘considerable’ overdiagnosis and overtreatment.
Their study, Effect of implementation of the mass breast cancer screening programme in older women in the Netherlands: population based study, was based on data from the Netherlands, where the national breast screening programme was extended to women aged 69 to 75 in 1998 and national guidelines recommend screening women up to the age of 75.
The researchers tracked all new cases of breast cancer diagnosed in Dutch women aged 70-75 from 1995 to 2011. Analysis of these figures revealed a sharp rise in the number of early stage diagnoses in this age group after national screening was introduced (from 248.7 to 362.9 per 100,000 women) but only a small absolute decrease in the number of advanced cases (from 58.6 to 51.8 cases per 100,000 women).
For every advanced stage cancer detected by screening among 70-75 year olds, around 20 early stage cancers were picked up – a trend that the researchers said could translate to significant overdiagnosis and overtreatment of an already vulnerable age group.
The team led by Dr Nienke de Glas of Leiden University Medical Centre warned that cancer treatments could impair quality of life, especially for older women, whose age and comorbidities make them more vulnerable to the side effects of cancer treatments that have ‘little obvious health benefit’.
Researchers concluded that for many older women, the ‘unfavourable effects’ of screening could ‘outweigh the benefits’, and that the decision to participate in screening programmes should be ‘personalised, based on remaining life expectancy, breast cancer risk, functional status and patients’ preferences’.
They recommended that routine breast cancer screening for women aged 70 and over should not be performed on a large scale, pending the results of a current Cancer Research UK trial examining data from the the NHS’s breast cancer screening programme.
It is hoped that the results of this large randomised controlled trial (which examines data from women aged up to 73) will allow investigators to assess the effects of screening on breast cancer incidence and mortality.