Staging Breast Cancer with MRI, the T. A Key Role in the Neoadjuvant Setting

SIMPLE SUMMARY: Neoadjuvant chemotherapy (NACT) indications have expanded from inoperable locally advanced to early-stage breast cancer. The pivotal role of magnetic resonance imaging (MRI) with morphological and functional modalities is making headway in the assessment of tumor size in the staging, residual tumor and prediction of response. Radiomics and radiogenomics MRI applications in the setting of the prediction of the response to NACT in breast cancer are continuously increasing. Nevertheless, there are still controversies regarding the indication of MRI in this setting. Given numerous publications and clinical trials regarding this field, we sought to summarize this complex literature to help clarify the role of MRI in evaluating the tumor size in the staging, response assessment, and surgical planning in early-stage breast cancer patients receiving NACT. ABSTRACT: Breast cancer (BC) is the most common cancer among women worldwide. Neoadjuvant chemotherapy (NACT) indications have expanded from inoperable locally advanced to early-stage breast cancer. Achieving a pathological complete response (pCR) has been proven to be an excellent prognostic marker leading to better disease-free survival (DFS) and overall survival (OS). Although diagnostic accuracy of MRI has been shown repeatedly to be superior to conventional methods in assessing the extent of breast disease there are still controversies regarding the indication of MRI in this setting. We intended to review the complex literature concerning the tumor size in staging, response and surgical planning in patients with early breast cancer receiving NACT, in order to clarify the role of MRI. Morphological and functional MRI techniques are making headway in the assessment of the tumor size in the staging, residual tumor assessment and prediction of response. Radiomics and radiogenomics MRI applications in the setting of the prediction of response to NACT in breast cancer are continuously increasing. Tailored therapy strategies allow considerations of treatment de-escalation in excellent responders and avoiding or at least postponing breast surgery in selected patients.