In women, breast cancer is the most common cancer in the United States, with 207,090 cases being diagnosed annually, according to the National Cancer Institute. A number of risk factors are linked to an increased potential of developing breast cancer. One of these risk factors is a history of another member of the family having been diagnosed with breast cancer.
Genetics
A woman's risk of breast cancer increases if a member of their family was diagnosed with breast cancer, especially if under the age of 50 at the time of diagnosis. However, familial breast cancer only accounts for 20 percent of breast cancer, the others being sporadic. The most well known genes known to increase the risk of breast cancer are the BRCA1 and BRCA2 genes, but other genes and syndromes have been linked to an increased risk of breast cancer.
Diagnosis and Prognosis
King and Colleagues from Washington University published in "Science" in 2003 showed that mutations in the genes BRCA1 or BRCA2 can increase a person's lifetime risk by up to 80 percent, depending on their age. (see reference in comment box) Most familial breast cancers occur at a younger age. The March 2010 issue of "Biomedical Central Cancer" showed a 10-year followup study that indicated that patients who developed breast cancer and had a BRCA1 mutation had a better prognosis than patients with sporadic breast cancer.
Screening
There are estimated to be thousands of alterations in the BRCA1 and BRCA2 genes. The 2009 April issue of the "Journal of Clinical Pathology" showed that different alterations in the genes influences the age of development of breast cancer and the risk of other cancers. However, a mutation on a gene linked to breast cancer increases a person's risk of breast cancer, but does not mean that they will develop breast cancer. Altering certain lifestyle factors that are also linked to increasing or preventing breast cancer may reduce the person's risk.
Prevention
Changing risk factors may decrease a high risk woman's chance of developing breast cancer. Research reported in the July 2004 issue of the "Journal of the National Cancer Institute" showed that women with mutations in the BRCA1 gene who breast fed for over a year reduced their risk of breast cancer. Women with a known family history of breast cancer should have regular surveillance. These patients, however, may be more sensitive to ionizing radiation. However, a study from the Memorial Sloan-Kettering Cancer Center in 2006 showed than routine mammography is unlikely to cause an increase in breast cancer in these patients.
The use of tamoxifen has been shown to reduce the risk of breast cancer in high risk patients, and the effect can persist even after discontinuation of the medication. While, some women may decide on prophylactic mastectomy which can reduce the risk of future breast cancer by up to 90 percent, according to the National Cancer Institute.
Other Cancers
BRCA1 and BRCA2 and other genes associated with breast cancer can also increase a person's risk of other cancers such as ovarian, cervix, pancreatic, colon, gall bladder, and others.
References
- National Cancer Institute: Breast Cancer
- "Biomedical Central Cancer"; Favourable Ten-year Survival in a Caucasian Population with High Probability of Herediatry Breast Cancer; Cortesi L., et al.; March 2010
- "Journal of Clinical Pathology"; Age-depedent Penetrance of Different Germline Mutations in the BRCA1 Gene; Al-Mulla F., et al.; April 2009
- "Journal of the National Cancer Institute"; Breast Feeding and the Risk of Breast Cancer in BRCA1 and BRCA2 Mutation Carriers ; Jernstrom H., et al.; July 2004
- "Cancer Epidemiology , Biomarkers and Prevention"; Effect of Mammography on Breast Cancer Risk in Women with Mutations in BRCA1 or BRCA2 ; Goldfrank D., et al.; November 2006
