QUALITY ASSURANCE IN BREAST-CANCER SCREENING CYTOLOGY - A REVIEW OF THE LITERATURE AND A REPORT ON THE UK NATIONAL CYTOLOGY SCHEME

The National Breast Screening Programme in the United Kingdom has had an external quality assessment (EQA) scheme for breast screening histo pathology since 1990. Recently, it was decided, by the Cytology sub-gr oup of the National Co-ordinating Committee for Breast Screening Patho logy, to institute two forms of cytology quality assurance. An EQA sch eme is planned with circulation of slides to pathologists, but this in volves extra time and effort from the participants at a time when gene ral pathology workloads are high. Because of this, a computer routine has been written to analyse the data already present within the Nation al Breast Screening Computer Systems, to enable the calculation of sen sitivity and specificity of fine needle aspiration, correlating the cy tology results with subsequent histology or follow-up mammography for lesions where no biopsy is performed. This routine uses standardised t erminology and calculations and, therefore, inter-unit comparisons can be made. Where problems are identified within a unit, the Quality Ass urance team can investigate the cause and institute appropriate measur es to correct the problem. This article details the procedures involve d in this audit and reviews the literature, recalculating the paramete rs in a standard manner for a number of publications. The results of t he cytology quality assurance routine from seven screening units in on e health region in the U.K. are presented and the measures taken to im prove the level of service are discussed.