Breast cancer. Coloured breast X-ray (mammogram) showing the presence of a malignant tumour (cancer, orange area at lower left) in a 91-year-old woman's breast. Breast cancer is the most common cancer in women. Symptoms include painless lumps in the breast, a dark discharge from the nipple, and an indentation of the nipple. Early diagnosis can be made by mammography or self-examination. The cancer can be effectively treated by surgery followed by a course of radiotherapy or anti- cancer drugs to destroy any remaining cancerous cells.