Invasive and non-invasive breast cancer can be distinguished from normal mammary gland or benign breast tumor by apparent diffusion coefficient in magnetic resonance imaging.

Abstract

Abstract Abstract #4011 Introduction: MRI (magnetic resonance imaging) has become increasingly important in the diagnosis of breast cancer and evaluation of the area to be resected. However, large amounts of information are buried in plain MRI, including apparent diffusion coefficient (ADC). This study measured ADC for normal breast tissue, benign breast tumor and malignant breast tumor, and tested the ability to differentiate malignant lesions from benign breast tumor or normal mammary gland.
 Patients and Methods: ADC was measured for 122 consecutive patients who visited our institute with breast abnormality from January 2007. Malignant breast tumor was diagnosed in 101 patients (invasive breast cancer, n=81; non-invasive cancer, n=20) and 21 patients displayed benign breast tumor (n=11) or normal mammary gland (n=10). A 3.0-T MRI system was used in this study and the motion-providing gradient added was 0 and 1000 s/mm2.
 Results: Mean ADC for the 101 breast cancer patients was 0.939±0.225 10-3 mm2/s, lower than that of the 26 benign or normal patients, at 1.247±0.269 10-3 mm2/s (p>0.0001, t test). Among breast cancers, mean ADC was 0.892±0.021 10-3 mm2/s for invasive lesions and 1.081±0.247 10-3 mm2/s for ductal carcinoma in situ. Each showed significantly lower ADC than benign or normal breast tissues (p>0.0001 each). Three cases of micro-papillary cancer were identified, and this type of cancer is known to display a worse prognosis. Mean ADC for these cases was 0.660±0.089 10-3 mm2/s, lower than the average for breast cancer. Furthermore, mean ADC in 46 cancer cases with histological grade II III was 0.857 10-3 mm2/s, lower than that of the 23cases with grade I tumor, at 1.023 10-3 mm2/s (p=0.0029).
 Conclusion: This study revealed that even non-invasive breast cancer can be distinguished from benign lesions by ADC. As ADC can be obtained rapidly without use of contrast enhancers, this approach has potential for application in breast screening. Furthermore, as aggressive cancers such as invasive micropapillary cancer or high-grade cancer show low ADC, use of ADC values as potential prognostic markers should be investigated. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4011.