This study compares the clinical performance of three digital mammography system types in a breast cancer screening programme. 28 digital mammography systems from three different vendors were included in the study. The retrospective analysis included 238 182 screening examinations of females aged between 50 and 64 years over a 3-year period. All images were double read and assigned a result according to a 5-point rating scale to indicate the probability of cancer. Females with a positive result were recalled for further assessment imaging and biopsy if necessary. Clinical performance in terms of cancer detection rate was analysed and the results presented. No statistically significant difference was found between the three different mammography systems in a population-based screening programme, in terms of the overall cancer detection rate or in the detection of invasive cancer and ductal carcinoma in situ. This was shown in both prevalent and subsequent screening examination categories. The results demonstrate comparable cancer detection performance for the three imaging system types operational in the screening programme.

Revised indicators to reflect the digital mammography era are anticipated in revised European Guidelines on breast cancer screening.

10568 Background: Breast cancer screening programmes reduce mortality but result in increased numbers of breast biopsies. Stereotactic and ultrasound-guided core needle biopsy yield similar results to each other and to open biopsy. Study: Analysis of prospectively-acquired data relating to 174,338 screening mammograms performed in BreastCheck between Jan 2001 to Oct 2004. Relative use of ultrasound and stereotactic guidance for core needle biopsy is ascertained, and malignancy yields analysed. Results: In this time period, 174,338 screening mammograms discovered a total of 2782 lesions requiring further assessment. Of 2760 complete records, 1066 were BiRads R3–5 (39%) and 1033 of these (97%) had CNB. Guidance was provided exclusively by ultrasound in 737 (71%), and by stereotaxis in 270 (26%) of cases. There were no differences in malignancy yield of ultrasound versus sterotactically-guided CNB of R4 and R5 lesions (approximately 50% and 90% respectively). The malignancy yield in R3 lesions was significantly higher when performed with stereotactic guidance (12%) than when performed with ultrasound-guidance (5%) and both were significantly higher than R3 biopsy malignancy yields reported in the literature. Conclusion: Almost all BIRADS 3, 4 and 5 lesions are biopsied. The relatively high malignancy yield in R3 biopsies, particularly those with calcification, supports current practice. No significant financial relationships to disclose.

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