Breast cancer is the most common cause of cancer in women and the second most common cause of cancer death in women in the U.S. While the majority of new breast cancers are diagnosed as a result of an abnormality seen on a mammogram, a lump or change in consistency of the breast tissue can also be a warning sign of the disease. Heightened awareness of breast cancer risk in the past decades has led to an increase in the number of women undergoing mammography for screening, leading to detection of cancers in earlier stages and a resultant improvement in survival rates. Still, breast cancer is the most common cause of death in women between the ages of 45 and 55. Although breast cancer in women is a common form of cancer, male breast cancer does occur and accounts for about 1% of all cancer deaths in men.
Research has yielded much information about the causes of breast cancers, and it is now believed that genetic and/or hormonal factors are the primary risk factors for breast cancer. Staging systems have been developed to allow doctors to characterize the extent to which a particular cancer has spread and to make decisions concerning treatment options. Breast cancer treatment depends upon many factors, including thee type of cancer and the extent to which it has spread. Treatment options for breast cancer may involve surgery (removal of the cancer alone or, in some cases, mastectomy), radiation therapy, hormonal therapy, and/or chemotherapy.
With advances in screening, diagnosis, and treatment, the death rate for breast cancer has declined by about 20% over the past decade, and research is ongoing to develop even more effective screening and treatment programs.