Mammographic Breast Density: it’s Role in Tumor Size Assessment with Imaging Techniques

Aims: To study the visual and automatic measurement of mammographic breast density (MBD) and its implicationsin tumor size assessment using distinct imaging techniques.Methods: Retrospective, observational study of the visual and automatic measurement of mammographic breastdensity according to the breast imaging data system (BI-RADS) in 212 patients with invasive unifocal breast cancer,excluding microinvasive lesions, who did not receive neoadjuvant chemotherapy. Tumor size assessment is comparedusing a linear regression according pathologic size with mammographic, US and MR size. The influence of MBD ineach technique of pathologic size was seen by Bland-Altman plot.Results: Patient’s mean age was 55, 7±9.9 year-old. The mean size of the lesion stablished by mammography was16.8± 10.4 (4 -70) mm, by US was 13.6±7.2 (5 – 55) mm and by MR 17.2 ±9.9 (5 – 66) mm. Mean pathologic sizewas 12.6 ±8.1 (0.3 – 55) mm. Automatic MBD mean was 25.2±16.78. BIRAD assessment with visual and automaticMBD measurements were correlated with a tendency of tumor size overestimation with visual method. Linearregression of tumor size according image techniques with pathologic size showed an adjusted r-square of 27.3% formammography, 41.8% for US and 51.7% for MR. The best correlation was seen with MR although has a tendencyto overestimate tumor size. Only tumor size assessed by mammography was influenced by MBD. With this technique,tumor size was best adjusted for those breasts with lower MBD.Conclusion: Visual measurement overestimates MBD versus automatic measurement according BIRADS categories.MR is the more accurate breast imaging technique for assessing tumor size independently of the BMD, which onlyinfluences in the mammographic tumor size estimation.