The clinical significance of breast MRI in the management of ductal carcinoma in situ diagnosed on needle biopsy

Objective: To identify the factors associated with invasive disease in ductal carcinoma in situ diagnosed on needle biopsy by analyzing breast magnetic resonance imaging findings with the histopathological factors of biopsy specimens. Methods: This was an institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study. Seventy-five ductal carcinoma in situ patients diagnosed by needle biopsy who underwent preoperative magnetic resonance imaging were retrospectively reviewed. The magnetic resonance imaging and histopathological variables were assessed between pure ductal carcinoma in situ and invasive breast cancer diagnosed on surgical specimens. Multivariable analyses were performed to determine the independent factors for invasion using a logistic-regression model. Results: The median age of patients was 55 (34-76) years. On dynamic magnetic resonance imaging, 60 cases out of 75 (80%) were classified as non-mass-like enhancement type and 15/75 (20%) were Mass type. In non-mass-like enhancement, 11/60 (18%) were ultimately diagnosed as invasive breast cancer. Lesion size (P = 0.027), signal intensity ratios (calculated as the signal intensity of detected lesions divided by the signal intensity of surrounding normal breast tissue; P = 0.032) on magnetic resonance imaging and the number of biopsycores containing cancer nests (P = 0.012) were each independently associated with invasion. Furthermore, each signal intensity ratio of invasive and non-invasive components of invasive breast cancer represented a value significantly higher than that of 49 pure ductal carcinoma in situ classified as non-mass-like enhancement (P = 0.001 and P = 0.034, respectively). Conversely, there were no significant magnetic resonance imaging findings to distinguish seven invasive breast cancer from among Mass type. Conclusions: Needle-biopsy-proven ductal carcinoma in situ cases with non-mass-like enhancement type might be sufficiently managed using breast magnetic resonance imaging features such as enhanced lesion size and signal intensity, incorporating the number of cancer-cores at needle biopsy specimen in the clinical setting.