Relationships Between Breast Edema and Axillary Lymph Node Metastasis in Breast Cancer

<b>Background/Objectives:</b> To investigate the association between MRI features of primary breast cancers with axillary status, aiming to identify possible imaging biomarkers. <b>Methods:</b> Patients diagnosed with breast cancer between 2021 and 2023 in our clinic were retrospectively evaluated, and those that presented as mass lesions on preoperative MRI examinations (<i>n</i>: 123) were included in the study. Patients with and without metastatic axillary lymph nodes (mALN) were compared in terms of breast density, background parenchymal enhancement, tumor size, location in the breast, distance from the skin, patient age, presence of edema, multiple foci, histopathological type and molecular subtype of tumors. In multifocal/multicentric cases, the largest lesion was taken into consideration. Prepectoral and subcutaneous edema were considered diffuse edema, while perilesional edema was considered focal edema. MannWhitney U/Student-<i>t</i> test, Chi- square/Fischer Exact tests and logistic regression analysis were used for statistical analyses as appropriate. <b>Results:</b> Axilla was positive in 88 patients. There was a statistically significant difference in terms of edema, age, molecular subtype, Ki-67 index, number of lesions, tumor size, and laterality between the two groups (<i>p</i> < 0.05). Univariate logistic regression analysis showed that all included variables were statistically significant (<i>p</i> < 0.05). Multivariate logistic regression analysis revealed that presence of edema (OR: 2.46 CI; 1.11-5.48, <i>p</i> = 0.027) and multiple lesions (OR: 1.86 CI; 1.01-3.43, <i>p</i> = 0.046) were significantly associated with mALN. There was no significant difference between peritumoral edema and diffuse edema. <b>Conclusions:</b> Our study showed a statistically significant relationship between the axillary status and the presence of edema and multiple tumoral lesions on MRI. These findings have a potential to serve as prognostic imaging biomarkers for predicting the presence of mALN. Further studies with larger case series are needed to support our findings.