Breast cancer is a disease which begins in the breast tissue; it’s the second most common type of cancer and mainly affects women (breast cancer is rare in men).
During 2005, over 185 000 women were diagnosed with breast cancer (see incidence of breast cancer). Left undetected and untreated, breast cancer can spread to other areas of the body. Where breast cancer has to spread to other areas, it is referred to as metastatic breast cancer and classed as stage 4.
The prognosis for stage 4 breast cancer is not good; the 5-year survival rate is only 16 percent. Given the high incidence and destructive nature of breast cancer, early prevention and treatment of this disease is a high priority.