A Comparison of Two View and One View Mammography in the Detection of Small Invasive Cancers : Results from the National Health Service Breast Screening Programme

Abstract

Objective— To examine the effect of using two view mammography in comparison with one view mammography in the detection of small (<15 mm) invasive cancers. Setting— Screening programme data from National Health Service breast screening programme (NHSBSP). Methods— Data were collated from all screening programmes in the United Kingdom on standard “Korner” returns (KC62 forms) for the screening year 1 April 1994 to 31 March 1995. The comparison of invasive cancer detection rates by programmes using one and two view mammography with indirectly age standardised invasive cancer detection rates. Results— Programmes using two views for women attending their prevalent screen (first screen) in the NHSBSP detected 3% more non-invasive/microinvasive cancers, 7% more large invasive cancers (⩽15 mm), and 42% more small invasive cancers (<15 mm) than programmes using one view mammography. Conclusions— The success of the screening programme depends largely on the ability of individual programmes to detect small invasive cancers. The results suggest that the benefit of using two view mammography is largely in the increased detection of these cancers.