Objective: To present results from the NHS breast screening programme (NHSBSP) from 1994 through to 1999 and to examine the extent to which interim targets are being achieved.
Methods: Data were collated from all screening programmes in the UK on standard statistical returns. Performance of the screening programme was evaluated using calculated targets based on comparison with the Swedish two counties (STC) randomised controlled trial.
Results: In the early years of screening (1988-1993), the NHS programme was detecting more DCIS but considerably less invasive cancers than expected, based on the STC trial. Since the screening year 1993/94 (1 April to 31 March) the standardised detection ratio (SDR) measure of the detection of invasive cancers has increased by 36% from 0.83 to 1.13. The SDR has been greater than 1 since 1996197 suggesting that the NHSBSP has only been screening as efficiently as the STC trial since this date. Uptake for screening has been relatively stable over time at approximately 75%.
Conclusions: The NHSBSP has made considerable advances in performance since its inception in 1988 and screening uptake and age standardised invasive cancer detection rates are (by 1999) well in excess of targets. The early years of screening were characterised by good uptake but a low sensitivity for the detection of invasive cancers. It is anticipated that the screening programme will have an increasing impact on breast cancer mortality, particularly in the 55-69 year age group over the coming years.