Although the specific cause of breast cancer is often unknown, a certain number of women may be genetically predisposed to developing it. A woman with the BRCA1 or BRCA2 gene mutation carries an inherited risk of developing breast and/or ovarian cancer. A woman is more likely to carry a gene mutation if she has:
- A family history of breast and/or ovarian cancer
- Been diagnosed with breast cancer before the age of 45
- Another family member with a BRCA gene mutation
Although hereditary factors usually account for only 5 to 10 percent of all breast cancer cases, women who carry the BRCA gene may have up to an 85 percent chance of developing breast cancer at some point in their lives.
Diagnosis of Breast-Related BRCA Gene Mutations
A simple blood test performed in a doctor's office is used to test for mutations in the BRCA gene. The blood is drawn from a vein in the arm, and then sent to a lab for DNA analysis. It may take three to four weeks for results to be available. Women who test positive for BRCA gene mutations often seek preventive care to reduce their chances of developing cancer, and there are several surgical and nonsurgical treatment options available to them. Women who receive negative test results may still be at risk for breast cancer, and should be screened on a regular basis.
Preventing Cancer from Breast-Related BRCA Gene Mutations
Women who test positive for a BRCA1 or BRCA2 gene mutation are advised to take special precautions to help reduce their risk of breast cancer. Precautions may include increasing screening frequency to detect any lumps as soon as they appear, chemoprevention medication to kill cancerous cells as soon as they are detected, or preventive surgery. Known as a prophylactic mastectomy, preventive breast cancer surgery involves the surgical removal of healthy breast tissue. This procedure often reduces a patient's risk of developing breast cancer by as much as 90 percent.
Many women with the BRCA gene who are undergoing surgery for cancer in one breast choose to undergo, during the same surgery, a prophylactic mastectomy on the unaffected breast, which helps eliminate the need for additional surgery, and further reduces the risk of recurrence. Prophylactic mastectomy is performed using the same techniques as treatment mastectomy, and may involve, depending on the risk of cancer and the patient's personal preference, removal of the breast tissue, nipple, areola and/or lymph nodes.
Being tested for the mutation after a breast cancer diagnosis can help in making a decision about treatment. Women who undergo breast reconstruction after a single mastectomy and then develop cancer in the other breast have fewer reconstruction options for that breast. If too much skin has been taken from other areas of the body during the first procedure, there may not be enough available for the second. During reconstruction, implants and tissue-based or fat transfer may be used.
Breast cancer in men is extremely rare. Men who have mutations in BRCA genes, however, have a dramatically increased risk of getting the disease. Approximately 50 percent of men who develop breast cancer have BRCA gene mutations.