According to the National Cancer Institute, 1 in 50 women will develop breast cancer by age 50 and 1 in 10 women will develop breast cancer by age 80. Breast cancer is the most commonly diagnosed cancer in women second only to skin cancer. Every year, more than 180,000 women are diagnosed with breast cancer and 45,000 women die from it. Breast cancer has been seen to occur more often in white women than African American or Asian women. Breast cancer has also been seen in men, but it makes up less than 1% of all breast cancer cases.
Breast cancer is a disease in which the breast cells grow and reproduce themselves abnormally. It can present as a lump, a thickening, or a skin change. Breast cancer is diagnosed histologically, which means that specific breast tissue changes have to be seen before the diagnosis is confirmed. When a tumor is analyzed, it is further defined by classifying it into stages. Breast cancer staging is used to provide an estimate of disease-free survival, overall survival, and the risk of cancer recurrence. It is also used to determine the course of therapy. A patient with a low-stage tumor has a greater chance of surviving breast cancer than a patient with a high-stage tumor, according to findings from the National Cancer Institute. (Staging is described further in Breast Cancer Staging.)
Both genetic and non-genetic factors contribute to the risk of breast cancer.
Further discussion of the effects of estrogen on breast and ovarian cancer risk can be found in the section The Role of Estrogen in Breast and Ovarian Cancer.
What are genetic factors that can contribute to breast cancer?
Extensive research has indicated that hereditary (also known as familial) cases of breast and ovarian cancer are caused by genetic factors that are influenced by a common environment. Thus, both genes and environment play a role.
Women with a familial form of breast cancer were typically found to have:
Genetic factors that can contribute to breast cancer are:
For women at all levels of risk to develop breast cancer, only mammography has been shown to be helpful in detecting breast cancer when it is still at an early stage. However, the following recommendations have been made for other forms of surveillance to encourage early detection:
Please note that the only monitoring technique that has been proven to be beneficial for individuals with a genetic susceptibility to breast or ovarian cancer is routine mammography screening. Yearly mammograms are recommended to women of average risk beginning at the age of 40 to 50 years. At this time, additional experimental approaches to surveillance of breast cancer are currently being evaluated, but to date are unproven to be helpful.
Once breast cancer has been diagnosed, five major types of treatment are commonly used. The therapy or combination of therapies that is undertaken depends upon the location, size, and staging of the tumor and the overall health of the patient.
The different treatments are:
Reviewed by Wendy Rubinstein, MD, PhD, Center for Medical Genetics, Evanston Northwestern Healthcare 8/03.