An evaluation of breast cancer screening in the South Thames (West) Regionof the UKNHS Breast Screening Programme: the first 10 years

We have determined the progress of breast canter screening in the South Tha mes (West) region of the UK National Health Service Breast Screening Progra mme (NHSBSP) from the start of screening in 1987 to 31 March 1997, by evalu ating uptake, cancer detection rates, and interval cancer rates. Regional p erformance measures have been compared with NHSBSP targets. Uptake rates have been consistently close to the target of 70%, although ma rginally lower than the national average. Between 1 April 1990 and 31 March 1997 the region detected 1161 invasive cancers at prevalent (brst) screen compared with a calculated age standardized expected number of 1164.2, a St andardised Detection Ratio (SDR) of 1.00 (95% CI 0.94-1.06). During the sam e period, for incident (subsequent) screens, the region detected 640 invasi ve cancers compared with an expected 602.6, an SDR of 1.06 (95% CI 0.98-1.1 5). The target SDR for both prevalent and incident screen is 1. The interva l cancer rates over the period I April 1990 to 31 March 1994 for 0-23 month s after a negative screen were 1.23 per 1000 (95% CI 1.06-1.42) compared wi th a current national target of 1.20 per 1000. The evidence presented suggests that NHSBSP targets for both invasive cance r detection and interval cancer rates can be achieved.