Risk Management: Living in the Past, Present and Future with Genetic Risk
While they may not appear to be sisters in a crowd, Byer and Shainman share something more compelling than physical resemblance. In 2009 the sisters learned that they both carry an inherited mutation in the BRCA1 DNA repair gene that increases the risk for breast, ovarian and other cancers. The information came after Byer was tested when surgery at age 48 revealed not only ovarian but also uterine cancer.
The sisters knew that their paternal grandmother died at age 33 of a “female cancer” when their father was 7, and that no one in the family talked about it. The genetic counselor Byer consulted didn’t even consider her to be at risk and was surprised by the results.
Shainman, 40 at the time, says she felt like she had been waiting for some kind of information that would explain the medical notes she found in her father’s closet while looking for old pictures for a birthday scrapbook.
“They were my grandmother’s medical records, and the only word I could make out in all the flowery writing from 1934 was ‘metastases.’”
BRCA1 and BRCA2, which stand for breast cancer susceptibility gene 1 and 2, are genes expressed in cells of breast and other tissues to help repair DNA and prevent uncontrolled cell growth. If they become mutated, the damaged DNA is not repaired, leaving the woman or man at increased risk for certain cancers.
Statistics indicate that 12 percent of American women (120 out of 1,000) will develop breast cancer in their lifetime, compared with 60 percent of women (600 out of 1,000) who have inherited the BRCA1 or BRCA2 mutation. In addition, women who carry the mutated genes are at increased risk of developing breast or ovarian cancer before menopause. BRCA1 mutations may also increase a woman’s risk of developing pancreatic cancer, as well as melanoma. BRCA2 mutations increase the risk of pancreatic, stomach, gallbladder and bile duct cancers, as well as melanoma.
Men with BRCA1 mutations may be at increased risk of developing breast cancer and, possibly, pancreatic, testicular and early-onset prostate cancers. However, male breast, pancreatic and prostate cancers appear to be more strongly associated with BRCA2 gene mutations. To further complicate matters, there are numerous variations of each gene driven by ethnicity.
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Victoria Seewaldt, an oncologist and director of the breast cancer prevention program at Duke Comprehensive Cancer Center in Durham, N.C., says it’s important to remember that not every woman who has a BRCA1 or BRCA2 mutation will develop breast or ovarian cancer. The mutation increases risk, she emphasizes.
“Some women have BRCA2, and they generally have potential for an ER-positive breast cancer with a good prognosis,” Seewaldt says. “Not all BRCA are created equal.”
We want to make sure every woman with a BRCA mutation who wants to be screened has that option.
Children of a parent with a BRCA mutation have a 50 percent chance of inheriting it, Seewaldt says, but they also inherit other genes that impact whether it is activated. In other words, the mutation might be the same, but how it plays out will be different because of the person’s individual DNA and environment.
It’s a philosophy Seewaldt has adopted at the Duke clinic, where each woman in the clinic is seen as a healthy woman at risk for getting cancer, called “previvors,” and Seewaldt counsels them about aggressive screening or prophylactic surgery. Prophylactic surgery includes a bilateral mastectomy to remove most of the breast tissue and the bilateral salpingo-oophorectomy (BSO) that removes the ovaries and a good portion of the fallopian tube.
While Seewaldt is more assertive in addressing the need for prophylactic surgery with women who carry the BRCA1 mutation, she tells women with BRCA2 they have more options.
Seewaldt takes into consideration their age, whether they have children and the mutation before she will agree to regular high-quality MRI screening as long as there is no abnormal biopsy, which will prompt a discussion with Seewaldt about prophylactic mastectomy.
“We want to make sure every woman with a BRCA mutation who wants to be screened has that option,” she says. “We have many who want to date with their breasts and want to get married with their breasts and bear children with their breasts.”
Seewaldt advises women to keep the past in the past and the future in the future and deal with what is happening now as a way to make it more manageable.