Usefulness of Breast MRI for Diagnosing an Extensive Intraductal Component of Breast Cancer: Comparison with Mammography and Ultrasonography

ABSTRACT

PURPOSE: An extensive intraductal component of breast cancer is a principal risk factor for local recurrence, and this is difficult to diagnose with performing only mammography. We investigated the usefulness of breast MRI for evaluating an extensive intraductal component of breast cancer, and we compared this modality with mammography and ultrasonography (US). MATERIALS AND METHODS: From March 2003 to July 2004, 90 patients underwent breast MRI among all the patients who were suffering with breast cancer and for whom an EIC was ultimately revealed to be present or not. A total 83 patients with stage I and II breast cancer were finally included in this study. EIC positivity was defined according to the imaging data as follows: 1) microcalcifications beyond the tumor shadow or malignant microcalcifications without a tumor mass on mammography, 2) tubular hypoechoic structures adjacent to the tumor or architectural distortion with calcifications beyond the tumor on US, and 3) linear or ductal enhancement, segmental or regional clumped enhancement, and spotty nodular or reticular enhancement adjacent to the tumor on MRI. EIC was present in 41 patients and this finding was negative in 42 patients. The results were then compared those results from mammography and US. RESULTS: The sensitivities of detecting EIC by mammography, US and MRI were 48.6%, 67.5% and 80.5%, respectively, and the corresponding specificities were 92.3%, 73.2% and 69.0%, respectively. In the cases that were suspected to be EIC positive on more than two imaging modality, the positive predictive value (PPV) was 78.1%. In cases that were suspected of being EIC positive on just one imaging modality, the negative predictive value (NPV) was 75.0%. CONCLUSION: Breast MRI provides good information about an EIC of breast cancer and it is a more sensitive study than mammography and US, yet the specificity for the detection of EIC is highest on mammography. A combined evaluation by mammography, US and MRI is the most accurate way to diagnose an EIC of breast cancer.