Aim of the study To optimize the diagnostic process of breast cancer and to evaluate the diagnostic value of imagining modalities in detecting the spread of breast cancer to axillary lymph nodes. Objectives of the study 1. To determine the features indicative of metastatic involvement of axillary lymph nodes in breast cancer by different imaging modalities. 2. To evaluate the diagnostic value of ultrasound in detecting axillary lymph nodes with metastases. 3. To evaluate the diagnostic value of mammography in detecting metastatic involvement of axillary lymph nodes. 4. To evaluate the diagnostic value of magnetic resonance imaging in detecting metastatic involvement of axillary lymph nodes. 5. To determine the features indicative of metastatic involvement of axillary lymph nodes in breast cancer by thermography and to evaluate the diagnostic value of this imaging modality. 6. To develop an informative prognostic model, involving tumor biological characteristics and features of imaging modalities, for discriminating a benign from a malignant axillary lymph node.Scientific novelty. This study is the first prospective study conducted in Lithuania that has analyzed the diagnostic value of imaging modalities in evaluating the status of axillary lymph nodes in breast cancer. Recently, there are doubts on necessity to apply surgical interventions in detecting the metastases of breast cancer to axillary lymph nodes. There is an ongoing discussion on the outcomes of lymphadenectomy and sentinel lymph node biopsy and quality of life among women with breast cancer. Therefore, more attention has been paid to biological tumor characteristics in choosing the strategies of breast cancer treatment and predicting survival […].