Magnetic Resonance Imaging And Comparative Study Of Triple-negative Breast Cancer

Background and PurposeMagnetic resonance imaging (MRI) technology has become one of the most accurate imaging method for clinical detection and diagnosis of breast diseases. Dynamic contrast enhanced MRI(DCE-MR) and diffusion weighted imaging (DWI) technology can not onlyprovide important information about morphology.but also reflect the pathological characteristics through revealing the blood perfusion and water molecule diffusion of lesions. Triple-negative breast cancer(TNBC) is a sort of high malignant and invasive tumor, the prognosis is poor and the survive time is short. Endocrine and targeted therapies usually can not decrease the tumor progress, and the remote metastasis is very common. Although there are lots of research about this disease, articles focused on its imaging appearance are few. Early diagnosis can provide some assistant for clinical therapy. The purpose of this paper is to explore the value of 3.0T magnetic resonance imaging for diagnosis of TNBC.Material and Methods1.The object of study:From May 2012 to December 2014, sixty-five patients performed with MRI examination who were confirmed by pathology, contained fifteen cases with TNBC, thirty cases with non-TNBC and twenty cases with benign breast lesions, aged from 27 to 63 years(median 51 years). None patients underwent any treatment, such as neoadjuvantchemo therapy, radiotherapy and puncture, before MR examination.Thirty sevenlesions were located in left breast,24 lesions in right breast,4 lesions in both breasts. On pathology,33 lesionswere infiltrating ductal carcinoma,1 lesionwas ductal carcinoma in situ,2 lesionswere infiltrating ductal carcinoma with carcinoma in situ,4 lesions wereintraductal carcinoma,1 lesion was intraductal papillary carcinoma,3 lesions were non especially invasive carcinoma,1 case was metaplastic carcinoma.Benign lesions contained adenosis of breast in 15 cases, of which 7 cases with fibroadenoma formation,2 cases with papillary epithelioma formation and one case with granulomatous mastitis, granulation tissue with abscess formation in one case, fiber adipose tissue hyperplasia in one case, fibroma in 2 cases, galactostatic cyst in one case.2.Methods:All patients were performed with conventional MR, DWI and DCE examination.They were divided into TNBC group, non-TNBC group and benign lesions group according to the pathological and immunohisto chemical results. Evaluated the MRI appearance, recorded and analyzed the shape (non mass or mass type), number(single or multiple), boundary, signal on T2W images, enhancement characteristics, apparent diffusion coefficient (ADC) value and the type of time-intensity curve(TIC) of lesions.Lymph node metastasis were recorded.Statistical software SPSS 19.0 was used to analyze data. The average differences between two groups were compared with t test. Measurement data were analyzed with randomized block design analysis of variance among three groups, to test normality and homogeneity of variance of samples; P< 0.05 was defined as significant statistically difference.Rates were compared with chi-square test and Fisher’s exact probability analysis method among three groups,and P< 0.05 was regarded that statistically difference was significant. The ROC curves were drawn to decide the best diagnosis threshold value for differentiating three groups.Result1. The average age of TNBC was 41.1 years old, which was lower than that of non-TNBC and benign groups. The average diameter of masses was 2.60cm in TNBC group, which was lager than that of the others groups. The lymph mode metastasis rate was 26.7% and 80% lesions showed mass like enhancement in TNBC group. There was no significant difference in age, the diameter and the location of tumor, mass/non mass like enhancement, lymph node metastasis and number of lesions among three groups. Pathological grade Ⅱ was 53.3% and grade Ⅲ was 40% in TNBC. Compared with non-TNBC group, which had statistically significant difference. There had significant statistically difference in the shape, edge, signal characteristics on T2WI, enhancement pattern, TIC type and ADC value among three groups (P<0.05).2. In mass type TNBC,round or oval in shape was seen in 58.3%, and smooth marge was seen in 41.7%, which were significant statistically difference compared with mass type non-TNBC. Mass type TNBCs were hypo-or iso-intensity in 66.7%, slight hyper-intensity in 16.7% and hyper intensity in 16.7% on T2W images. After contrast media injection, mass type TNBC showed homogenous enhancement in 41.7%, inhomogenous enhancement in 33.3% and rim enhancement in 25.0%. The TIC type was Ⅲin 66.7%, Ⅱ in 25.0% and I in 8.3%. Compared mass type TNBC with mass type non-TNBC, there had no significant statistically difference in signal on T2WI, enhancement manner and TIC type.3. Compared mass type TNBC with mass type benign lesions, there had no significant statistically difference in location, shape and edge of lesions, but there had significant statistically difference in signal on T2WI, enhancement manner and TIC type. Mass type benign lesions usually showed slight hyper intensity (41.2%) or hyperintensity (23.5%), homogenous enhancement(82.4%), I type (35.3%) or II type(47.1%) TIC.4. The average ADC value was 1.2×10-3mm2/s in mass type TNBC, which was higher than 0.8×10-3mm2/s in mass type non-TNBC, and lower than 1.4×10-3mm2/s in mass type benign lesions. According to the ROC curve, the best diagnosis threshold value of ADC was 0.867×10-3mm2/s for differentiating TNBC and non-TNBC,the sensitivity was 83.3%, and the specificity was 82.6%; which was ADC=1.04×10-3mm2/s for differentiating TNBC and benign lesions, the sensitivity was 77.8%, and the specificity was 91.7%.Conclusion1. Infiltrating ductal carcinoma is the more often pathology type, and Ⅲ level is the more often clinical pathological staging in TNBC.2. Rim enhancement is not the characteristic appearance of TNBC, which can’t differentiate with non-TNBC.3. The value of rim enhancement, TIC type and hyper intensity on T2W image sin differentiate benign lesions from malignant lesions is lager than in differentiate TNBC from non-TNBC.4.When a large breast mass is found in young adult, and with smooth edge, round or oval shape, Ⅲ type TIC and high ADC value, TNBC must be take into account.