TUESDAY, Feb. 28, 2023 (HealthDay News) — Although BRCA1 or BRCA2 gene mutations are associated with breast and ovarian cancer in younger women, those over 50 continue to have a high risk of breast cancer.
That’s true even if they didn’t have breast cancer before, new research shows.
“What is striking about our results is that breast and ovarian cancers were the most common cancers and that is concerning, given that we know how to reduce the risk of cancer in women who have these genetic risk factors,” said study leader Kelly Metcalfe. , a professor of nursing at the University of Toronto.
To study this, her team followed more than 2,200 women between the ages of 50 and 75 from 16 countries. These women knew they had a BRCA mutation and had no prior cancer diagnosis.
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The risk that these women would develop any form of cancer after age 50 was 49% for those with a BRCA1 mutation and 43% for those with a BRCA2 mutation.
It was even higher for those who had no surgery to reduce cancer risk, such as preemptive removal of both breasts, both ovaries and fallopian tubes. For those women, the risk was 77% for those with a BRCA1 mutation and 67% for those with a BRCA2 mutation.
About 15% of the women studied had undergone a preventive bilateral mastectomy. In approximately 43%, both ovaries and fallopian tubes were removed before age 50.
These women had the lowest risk of cancer at only 9%.
“Our analysis highlights the effectiveness of these risk-reducing surgeries and emphasizes the need for both individuals and health care providers to consider clinical guidelines and recommendations for their cancer risk, including how their genetics may affect them even later in life,” Metcalfe said in a news release from the university.
She noted that access to risk-reduction surgery may be limited in some countries — a limitation of the research. Researchers have not assessed whether and how often women received genetic counselling.
“We do not know whether the participants in our study received additional education about their increased risk of cancer as they age, nor are we able to determine why some of these women chose to forego preventive surgery before age 50,” said Metcalfe. . “However, it is important to point out that screening only decreases [death] by increasing the chance of early detection of cancer, it does not reduce the risk of developing cancer.”
There is no good screening method for ovarian cancer. National Comprehensive Cancer Network guidelines recommend that women with a BRCA1 mutation have their ovaries and fallopian tubes removed between the ages of 35 and 40 and those with a BRCA2 mutation between the ages of 40 and 45.
Metcalfe hopes advances in genetic testing will help more women know their risks. Future studies will look at women’s decision making about surgery and their understanding of risk.
Low thresholds for genetic testing will save lives, said Metcalfe, who expects it to become a mainstay of cancer care in Canada. Regardless of family history, people can pay a small fee to test for BRCA1 and BRCA2 mutations through Screen Project Canada.
“It’s been more than 25 years since clinical trials for BRCA1 and BRCA2 began in Canada and the United States. We’ve come a long way in reducing cancer incidence, but not far enough,” Metcalfe said. “Most cancers that result from these two genes are preventable. We need to give women the best chance of a cancer-free life.”
Research findings were recently published in the journal Cancer.
The US Centers for Disease Control and Prevention has more information on the BRCA1 and BRCA2 genes.
SOURCE: University of Toronto, press release, February 24, 2023