Nationwide Cluster-randomised Trial of Extending the NHS Breast Screening Age Range in England

In 1988, the national Breast Screening Programme (BSP) began offering women aged 50-64 years triennial mammographic screening and full national coverage was achieved by the mid-1990s.

In 2003, the age range for triennial screening was extended from 50-64 to 50-70 years; proposals from committees in the Department of Health to randomise this age extension and thereby to obtain reliable information on both the risks and benefits of additional screening at ages 65-70 were not adopted.

Currently, 80 breast screening units cover all of England, each responsible for a defined area, and each year they invite about 2.8 million women aged 50-70, with 2.0 million accepting. The BSP sets standards for the screening units and monitors performance through its national quality assurance network.

In 2007, the Prime Minister announced plans for eventual extension to the range 47-73 years. This offered another opportunity to obtain reliable evidence about the effects of extending the age range of triennial screening. Hence, a trial of this age extension has begun, in which only half are offered extra screening, with the effects monitored through routinely collected NHS statistics.

Following a 2009-10 pilot study of the acceptability of cluster-randomisation of additional screening at ages 47-49 and 71-73 in 5 breast screening units, the AgeX trial extended recruitment to about five-sixths of the breast screening clinics in England, and this cluster-randomisation continues.