Radiologists monitoring a 70-year-old female patient with metastatic endometrial carcinoma (cancer of the epithelial tissue) undergoing external beam radiotherapy. Endometrial carcinoma is cancer of the endometrium (layer of tissue that lines the uterus). Cancer that spreads to other body parts is known as metastatic. External beam radiotherapy is a localised treatment where a linear accelerator is used to deliver precise beams of radiation to a tumour. The radiation kills or slows the growth of the cancerous cells by damaging their DNA (deoxyribonucleic acid).