Effect of NHS breast screening programme on mortality from breast cancer in England and Wales, 1990-8: comparison of observed with predicted mortality
How effective is screening for breast cancer ?
The introduction of an NHS breast screening programme, along with improvements in treatment for breast cancer, led to a 21% reduction in breast cancer deaths in England and Wales between 1990 and 1998, finds a study in this week's BMJ.
Using national data on breast cancer deaths for 1971-89, Blanks and colleagues were able to predict the number of deaths for 1990-8. The effect of screening and other factors on breast cancer deaths during this period was then estimated by comparing observed deaths with those predicted among women aged from 50-54 and from 75-79 years, the effect of screening being restricted to certain age-groups.
They found that in 1998, estimated deaths from breast cancer were 21% below that predicted in the absence of screening or other effects in women aged 55-69. Of this fall, 6-7% was as a direct effect of screening, and equates to 320 prevented deaths. Other factors, such as improvements in treatment and presentation of cancers at an earlier stage, also play major roles in the substantial reduction in deaths from breast cancer.
Despite several limitations in projecting deaths into future years, the authors are confident that further effects from screening, together with improved treatments, should result in yet further reductions in breast cancer deaths, particularly for women aged 55-69, over the next 10 years.
Contact:
Kate Husher or Erica Boardman at Press Office, The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP E-mail: press@icr.ac.uk