The breast consists of a series of mammary glands interconnected by tubes known as mammary ducts, which carry milk to the nipple during lactation. The mammary glands and ducts are embedded in adipose tissue and the conjunctive tissue, which together with the lymphatic tissue make up the breast. Breast cancer is the abnormal and disordered growth of the cells of this tissue.

Most tumours occurring in the breast are benign tumours, which are non-cancerous and are caused by fibrocystic nodules. The fluid they contain can be drained off and any pain relieved. Benign tumours are largely related to genetic factors. Their symptoms are pain and inflammation, but they do not spread to other parts of the body and are not dangerous.

There are however malign tumours, which are either localized or have spread through the blood or lymphatic vessels, giving rise to metastasis, a cancer in an organ different from that where they originated. Of all the cases of breast cancer, only from 7% to 10% present metastasis at the outset.

15,000 new cases are diagnosed in Spain every year, and one in every 16 or 18 Spanish women are expected to suffer from breast cancer. Breast cancer is the primary cause of death from cancer in women between the ages of 45-55 years, while the the rate of cure in Spain is approximately 60%. Early detection, before the tumour has had the chance to spread, brings the rate of recovery up to almost 90%.