Researchers have known for years that women carrying BRCA (breast cancer gene) mutations have a higher risk of breast cancer. Now, a recent study shows that those women are being diagnosed with breast cancer earlier than women without the genetic mutations. The study may have implications on when women with BRCA gene mutations should begin cancer screening.
“Currently, BRCA positive women are counseled to start screening by 25 years, or five to ten years earlier than their youngest affected family member. However, our findings show that we may need to continue to follow these trends with future generations, and make changes accordingly in order to best advise and care for women at greatest risk,” said Jennifer Litton, M.D., assistant professor in MD Anderson’s Department of Breast Medical Oncology, in the cancer center’s news release about the study.
BRCA1 (breast cancer gene 1) and BRCA2 (breast cancer gene 2) are two tumor suppressor genes that, when functioning normally, help repair damage to DNA (a process that also prevents tumor development). In 1994, researchers discovered that women who carry mutations of BRCA1 or BRCA2 are at higher risk of developing both breast and ovarian cancer than women who do not have these genetic mutations. Women with BRCA1 mutations account for 5% to 10% of all breast cancer cases.
“In our practice, we’ve noticed that women with a known deleterious BRCA gene mutation are being diagnosed earlier with the disease than their moms or aunts,” said Litton, in the news release. “With this study, we looked at women who had been both treated and had their BRCA testing at MD Anderson to determine if what we were seeing anecdotally was consistent scientifically, a phenomenon known as anticipation.”
To conduct the study, Litton and her colleagues identified 132 breast cancer patients with BRCA mutations at MD Anderson between 2003 and 2009. In reviewing the medical records of the patients, the researchers found that 106 were had a female family member in the previous generation who also had a BRCA-related cancer, either breast or ovarian. According to MD Anderson, age at diagnosis, location of mutation and birth year were recorded in both the older (gen1) and younger (gen2) women.
The study found that in gen2, the median age of diagnosis was 42, compared to age 48 in gen1. In comparing generations within a family, the median difference was six years. By using new mathematical models to evaluate for anticipation, the difference in age between generations was 7.9 years.
