Breast cancer, axial section. Coloured sequence of bilateral breast magnetic resonance imaging MRI scans showing a malignant cancerous tumour white mass at right of the left breast in a 58 year old patient. This is an adenocarcinoma. Breast cancer is the most common cancer in women. It can be treated by excision of the tumour if it is caught early. Radiotherapy and chemotherapy are often used as well as surgery to prevent the tumour from regrowing.