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What is Hereditary Breast Cancer?

Around 200,000 women are diagnosed with breast cancer every year in the United States. Around 10% of those cases are estimated to be hereditary or caused by a genetic mutation of two specific genes that is found in families and passed from generation to generation.

Fast Facts about Hereditary Breast Cancer

Hereditary breast cancer affects a small segment of the general population. It is caused by the mutation of BRCA1 and BRCA2 genes. There is a blood test available for the discovery of who has this gene mutation. Certain populations of people have a much great risk of carrying the BRCA1 or BRCA2 mutation. There are no outward signs that people are a carrier of the mutated gene, only a blood test can confirm the diagnosis.

If the gene mutation is present, there are life style changes that can be done to decrease the risk. There are also some proactive measures that can be taken such as Tamoxifen therapy or surgical intervention. Knowledge is power in this situation. Become as educated as possible if there is a diagnosis of BRCA1 or BRCA2 gene mutation. Discuss all possibilities with the genetics counselor, the physician, and other family members with the same diagnosis. Finally, consider being part of a clinical trial offered by the National Cancer Institute.

Causes of Hereditary Breast Cancer

During the mapping of the human genome, a gene that was associated with breast cancer was discovered. The BRCA1 gene was found on chromosome 17. BRCA stands for BReast CAncer susceptibility gene. During further mapping a second gene BRCA2 was discovered this time on chromosome 13.  It is a mutation in the BRCA1 or BRCA2 gene that can cause hereditary breast cancer to occur.

Risk Factors for Hereditary Breast Cancer

Females and males who carry the mutated form of BRCA1 or BRCA2 gene are at risk for developing breast cancer. Females are also at higher risk of developing ovarian cancer. The risk of developing breast cancer in the general population is about 12%. The risk of developing breast cancer for those with a mutated BRCA1 or BRCA2 gene is around 60%.

Symptoms of Hereditary Breast Cancer

There are no outward signs and symptoms that a person carries the mutated BRCA1 or BRCA2 gene. The signs and symptoms of hereditary breast cancer are the same as any breast cancer. People feel a lump in their breast, notice skin changes, or the mass is discovered during a routine physical. Some breast cancers are only detected by the use of mammography.

Diagnosing Hereditary Breast Cancer

The hereditary mutated gene that can cause breast cancer is diagnosed with a blood test. This test is not done on the general population, but rather in people with a strong family history of breast and other cancers. One way to determine who is at risk is take a family history and establish a breast cancer rate above that of the normal population in the genetic line. Then testing of someone who has the disease to look for the mutated gene is done. If a mutated BRCA1 or BRCA2 is found, then testing of other family members is usually recommended.

Jewish women are at a higher risk of developing hereditary breast cancer at an early age than non-Jewish women. Ashkenazi Jewish population women with first degree relatives (mother, sister, and daughter) who have breast or ovarian cancer should be tested. This same population should be tested if two second degree relatives (aunt, grandmother) on the same side have been diagnosed with breast or ovarian cancer.

Non-Ashkenazi Jewish women should be tested if they have two first degree relatives who develop breast cancer under the age of 50. They should be tested if they have three or more first or second degree relatives who develop breast cancer regardless of the age at diagnosis. Another red flag is having a first degree relative develop bilateral breast cancer (both breasts). Having two relatives develop ovarian cancer at any age is also a signal that testing needs to be done.

Genetic counseling is generally done before blood testing occurs. If the blood test is positive, genetic counseling will be continued. It is devastating news when patients find out they have the mutated gene that may cause cancer. That leaves them with some hard decisions to make.

Treatment Options for Hereditary Breast Cancer

There is no way to fix the mutated gene at this point. However, women who test positive can be more vigilant about breast cancer screenings. Your physician will probably order routine mammograms and frequent breast examinations by a clinician as well as an MRI. Some women may also choose to take Tamoxifen. This drug will decrease the risk of developing breast cancer by around 50%.

Other women may choose to have a bilateral mastectomy as well as having both ovaries removed. This is a radical decision that unfortunately does not always prevent the person from developing cancer. All options need to be thoroughly discussed with your physician before any course of action is undertaken.

There are also clinical trials that are underway for those that are BRCA1 or BRCA2 carriers. Access the National Cancer Institutes website for information or discuss this with your physician.

Prevention of Hereditary Breast Cancer

While you can’t prevent inheriting the mutated genes, you may be able help prevent developing cancer. If the decision is made to have surgery to reduce the threat of cancer, it needs to be done at an early age. Typically those who develop cancer due to genetic mutation are diagnosed prior to age 50.

Having children after age 30 increases the risk of breast cancer. However, breast feeding decreases the risk, probably due to hormone mediation. Taking oral contraceptives may decrease the risk of ovarian cancer. However, that may be a double edged sword as oral contraceptives may slightly increase the risk for breast cancer.

Being obese tends to increase the risk of developing breast cancer. It also may increase mortality rates of ovarian cancer. A fatty diet is also associated with increased breast cancer levels. The good news is physical exercise decreases the risk of developing breast cancer. Alcohol consumption may increase the risk of breast cancer; however, it is unclear if stopping consumption will decrease the risk.

Coping with Hereditary Breast Cancer

The power of knowing that there is a genetic predisposition to cancer can be very scary but also very empowering. The BRCA1 and BRCA2 mutations do not mean that a person will get cancer. It does give people the power to be more vigilant, reduce other risk factors as much as possible, and to educate themselves on the latest information.

Where to Find More Information:
BreastCancer.org – Genetics
CancerResearchUK.org – Breast Cancer Genes
BreastCancerCare.org.uk – Breast Cancer in Families