In the USA, studies show that about one in eight women is likely to develop invasive breast cancer in her lifetime. Among several factors, inherited gene mutations (BRCA1, BRCA2), as well as acquired gene mutations (tumor suppressor genes, oncogenes etc.), are believed to play a role in tumorigenesis. Of these, inherited gene mutations, as the name suggests, run in the family. If a woman’s mother, aunt, sister, or grandmother have been diagnosed with breast or ovarian cancer, if she carries a mutation in the BRCA1 or 2 genes, or if she carries a mutation in one of many genes associated with breast cancer (TP53, PTEN etc.), she is said to have a very high risk of developing breast cancer in her lifetime.
For women carrying the BRCA1 mutation, the average risk of developing breast cancer in their lifetime is 55-65%, although the risk could be as high as 80% in some families. For those with the BRCA2 mutation, the risk is reported to be about 45%.
Similar to breast cancer, inherited mutations in the BRCA1 and BRCA2 genes can predispose a woman to ovarian cancer. Additionally, several other factors including mutation in a gene that causes colon cancer, smoking, hormone replacement therapy, polycystic ovary syndrome, etc. also increase the risk of ovarian cancer in women.
Surgical removal of both breasts or a double mastectomy is known to reduce the chances of breast cancer by about 95%. If a woman has cancer in one breast and is also carrying the mutated gene, then removing the unaffected breast is suggested. Since breast cancer requires circulating hormones to grow, removal of a woman’s ovaries (oophorectomy) and Fallopian tubes is reported to decrease her probability of her having breast cancer in her lifetime by 50%. Oophorectomy with removal of Fallopian tubes in pre-menopausal women also cuts the ovarian cancer risk by 80-90%. Current research points to fallopian tubes as possible site of origin of ovarian cancers and hence removing both the fallopian tubes helps in decreasing the risk.
Being diagnosed with either one of the cancers or finding out that she has a high-risk gene mutation leaves a woman to make some tough choices. There are medical and psychological problems to be overcome. The Susan G Komen Foundation reports that the rate of bilateral mastectomies has been increasing for a number of reasons, and even without a faulty gene, some women are opting for double mastectomies when diagnosed with cancer in one breast.
In this regard, famous personalities like actress Angelina Jolie-Pitt have come forward with a clear message. Mrs. Jolie-Pitt underwent a double mastectomy about two years back, as her mother, aunt, and grandmother were all diagnosed, and later succumbed to breast cancer. Just today, she revealed that she also underwent surgery to remove her ovaries and fallopian tubes recently. As she wrote in the NY Times Op-Ed, “I did not do this solely because I carry the BRCA1 gene mutation, and I want other women to hear this. A positive BRCA test does not mean a leap to surgery. I have spoken to many doctors, surgeons, and naturopaths. There are other options. Some women take birth control pills or rely on alternative medicines combined with frequent checks. There is more than one way to deal with any health issue. The most important thing is to learn about the options and choose what is right for you personally.”
Written by Mangala Sarkar Ph.D.