Relevance of Mammography Associated with Echography in the Breast Cancer Screening

Abstract

INTRODUCTION: the echographic evaluation may reveal small breast cancers uncharacterized with mammography. OBJECTIVE: To compare the diagnostic yield, defined as the proportion of women with positive screen test results and positive reference standard, and performance of screening with mammography versus mammography plus echography in women with breast cancer. METHODS: 5609 women participated, from November 2009 to March 2011, submitted to mammographic screening, following age criterion (> 40 years) in the absence of clinically palpable lump, coming from the Diagnostic Center for Detection and Monitoring of the Oswaldo Cruz Alemao Hospital (DCDM -OCAH). All underwent cynical, mammographic and echographic assessment. The imaging tests were performed by two radiologists indistinctly. The reference standard was defined as a combination of pathology and 12 months follow-up for and was available for 4483 (79. 9%) of the 5609 eligible women. We calculated the diagnostic yield, sensitivity, specificity of mammography, echography and the combination of both methods, as well as the positive predictive value of biopsy recommendations for mammography versus the other forms of study considered. RESULTS: One hundred and nineteen women (122 breasts) were diagnosed with cancer: 45 suspects on mammography alone, 30 on mammography plus echography, and 46 with echography alone. In only one case, none of the imaging methods showed malignancy. The diagnostic yield of mammography was 10. 0 per thousand women screened (45 of 4483), increasing to 16. 7 per thousand (75 of 4483) when combined with echography. The additional income was 6. 7 per thousand women screened (95% CI, P = 0. 002). The diagnostic sensitivity of mammography was increased from 37% to 72% when combined with echography (P = 0. 001). of the 46 tumors detected by echography alone, 30 (65%) were invasive, with an average size of 16mm (range 09- 41mm) and 37 of them (80%) had negative lymph nodes. The specificity of mammography versus mammography plus echography was 97% and 96% respectively. The positive predictive value for biopsy after mammography diagnostic investigation was 57% and by both methods 60%. CONCLUSIONS: the addition of echography to mammography improves your diagnostic yield of 10. 0 to 16. 7 per thousand women over 40 years, increase discreetly the ratio of false positives.