Probably not. To advise you on whether or not to be tested for mutations in the breast cancer genes I would need to know a lot more about your family history. First of all, you should know that only about five to 10 percent of all the women diagnosed with breast cancer have mutations in the BRCA-1 and BRCA-2 genes; and you can inherit these high-risk mutations from either side of your family. According to the National Cancer Institute (NCI) you’re most likely to have a mutation in one of these genes if you have a family history of:
- Three or more close blood relatives who developed breast cancer, ovarian cancer, or both.
- Breast or ovarian cancer (or both) occurring before age 50 in one or more close female relatives.
- One or more close blood relatives who developed two primary breast tumors (two in the same breast or one in each).
- One or more close male blood relatives who developed breast cancer.
- Ashkenazi (Eastern European) Jewish ancestry and breast or ovarian cancer or both.
Even if you fall into one or more of these categories, the NCI says your risk of having one of the genetic mutations is only about 17 percent.
Women who decide to be tested and learn that they don’t have a mutation in one of the genes still face the same risk of breast cancer as all other women. Today’s testing doesn’t exclude the possibility of having another unidentified genetic abnormality that would increase your risk. Women who have a positive test result ( i.e., a proven mutation in BRCA-1 or BRCA-2) have to consider what to do next. One option is taking tamoxifen, an estrogen-blocking drug that can reduce breast cancer risk. Another is participating in a clinical trial on breast cancer prevention. Some women opt to have their breasts and ovaries removed preventively – but even this doesn’t guarantee that cancer won’t develop in residual tissue. And there is a downside: some women become depressed, anxious, or angry when they find out that they have these mutated genes. In addition, there’s also the possibility of discrimination, in insurance coverage or employment, for women who test positive.
If your family history suggests that your risk of breast cancer is high, I suggest getting genetic counseling from a qualified professional in order to decide whether or not to be tested and to prepare yourself for dealing with the possibility of a positive result.
Andrew Weil, M.D.