We know that women who inherit harmful mutations in the genes BRCA1 or BRCA2 have a sharply increased risk of developing breast and/or ovarian cancer at an early age (prior to menopause). In fact, women with inherited BRCA1 or 2 mutations are about five times more likely to develop breast cancer — and at least 10 times more likely to develop ovarian cancer — than women without such mutations, according to the National Cancer Institute.
BRCA stands for BReast CAncer susceptibility. But does the increased risk apply only during a woman’s younger years or does it continue over the entire course of her life?
Women with inherited mutations in the BRCA1 or 2 genes do have a higher lifetime risk of breast and/or ovarian cancer than women without these mutations. The increased risk never really goes away as a woman ages.
It’s important to read risk-related statistics carefully. Picture a woman in her late 70s who decides to be tested and learns that she carries a BRCA1 mutation. From a statistical standpoint, she has had a 40-80 percent chance of developing breast cancer and a 40-60 percent chance of developing ovarian cancer during her lifetime, beginning at age 30.
But that risk is cumulative. It increases by one to two percent a year, so that by the time she is 50, she has lived past more than half of her risk. It does not mean she has a 60 percent chance of developing either of these diseases every year, or even over the next 10 years.
Keep in mind that the risk of cancer in the general population also rises with age. Over the next 20 years, the woman’s likelihood of developing breast or ovarian cancer is about 20-30 percent, while the general population risk is 10 percent for breast and one percent for ovarian. So her risks are still higher than average, but not by as much.
If you have questions about your cancer risk, at any age, you can gain a better understanding of your situation by talking with a genetic counselor. You can also submit your question online to the Dana-Farber team.