Retrospective evaluation of the relationship between diffusion-weighted imaging findings and molecular biomarkers on 3.0 tesla MRİ in malignant breast masses

The aim of our study was to evaluate the contribution of diffusion-weighted imaging (DWI) and apperent diffusion coefficent (ADC) values obtained by 3.0 Tesla magnetic resonance imaging (MRI) to the diagnosis and the relationship between prognostic factors and ADC in breast cancer. Between May 2018 and January 2020, 62 patients who underwent dynamic breast MRI and DWI in our department and whose post-op pathology is compatible with invasive breast carcinoma were enrolled in the study. Minimum ADC, mean ADC and lesion/normal breast mean ADC ratio from the DWI findings of the patients were evaluated in terms of classical histopathological characteristics and molecular prognostic biomarkers of the masses. In addition, dynamic breast MRI findings were compared with DWI and histopathology findings. A positive correlation between mean ADC and size, also a negative correlation between minimum ADC, lesion/normal breast mean ADC ratio with grade was found. There was no significant correlation between ADC values and molecular biomarkers (histopathological prognostic factors such as ER/PR status, Her2neu and Ki-67), other histopathological features, especially molecular subtypes of tumors. A significant correlation was observed between multifocality, multicentricity and nonmass enhancement status with high ADC values. In receiver operating characteristics (ROC) curve analysis; it was found that the mean ADC threshold value of ≤ 1.03 10-3 mm2/s had a high sensitivity, specificity and area under curve (AUC) value when detecting malignant lesions in normal breast tissue. It was observed that HER-2 enriched molecular subtype, accompanied by axillary lymph node (LN) involvement, ER/PR negative and Her2neu positive tumors had a larger size. In addition, higher rates of multifocal and nonmass enhancement were found in Her2Neu positive tumors. Extensive in situ component in tumors with multifocal, multicentric or nonmass enhancement; axillary LN involvement was more common in multifocal tumors. Mild peritumoral lymphocytic infiltration was detected in all masses with type 1 enhancement. In conclusion, it is believed that DWI findings and ADC values may perform a role in determining the prognosis of breast cancer.