LAUSR

Magnetic Resonance Imaging (MRI) is used to assess the response to Neoadjuvant Chemotherapy (NAC) when used in patients with breast cancer. This retrospective observational study compared patterns of tumour response at mid-chemotherapy and post-chemotherapy MRIs to histological outcomes. 118 cases of breast cancer, from a local database, were included. There was a significant association between complete pathological response in resected breast tissue and complete radiological response on both mid-chemotherapy MRI (p = 0.007) and post-chemotherapy MRI (p < 0.001). In patients who had both scans,100% of those with complete response at mid-chemotherapy scan maintained this response pattern. In those who had both scans, complete response at the mid-chemotherapy scan had a PPV for complete pathological response in resected breast tissue of 92% compared to 64% in those with complete response that was not achieved until the post-chemotherapy scan. There was a trend towards an association between early complete radiological response and complete pathological response (p = 0.124). Both scans have significant prognostic value. A mid-chemotherapy scan may have superior prognostic value when complete response is achieved, though larger studies are needed to determine the significance. 100% maintenance of complete radiological response after the mid-chemotherapy scan highlights the possibility that some post-chemotherapy scan could be avoided.