Genetic Breast Cancer Diagnosed Years Earlier in Younger Generations

Women with mutations in the breast cancer genes, nicknamed BRCA1 and BRCA2, are being diagnosed with breast cancer six to eight years earlier than their mothers and aunts who also had such mutations, a new study says.

The 106 women in the study with BRCA mutations were diagnosed with breast cancer at age 42, on average, whereas their family members of the previous generation also believed to have BRCA mutations had been diagnosed at age 48.

This could mean that breast cancer is, in fact, developing earlier in younger generations, the researchers said. In medicine, when an inherited disease develops at an earlier age, or in a more severe form, in the children of parents who also had the condition, doctors refer to this as "anticipation."

"In BRCA-positive women with breast cancer, we actually might be seeing true anticipation, said study researcher Dr. Jennifer Litton, an assistant professor at The University of Texas MD Anderson Cancer Center. "This suggests more than the mutation could be involved, perhaps lifestyle and environmental factors are also coming into play."

However, the earlier diagnosis could also be due to advances in the screening methods used to detect breast cancer, so more studies are needed. In 2007, the American Cancer Society recommended women at high risk for breast cancer, including women with BRCA mutations, get screened with Magnetic Resonance Imaging (MRI) in addition to getting mammograms. MRI is thought to catch small tumors earlier than mammography.

Anticipation and screening

Women with BRCA mutations are currently recommended to start screening at the age of 25, or 5 to 10 years earlier than their youngest affected family member. Right now, these recommendations appear to be appropriate. But if anticipation is occurring, women with BRCA mutations may need to be screened earlier, Litton said.

"If it is real, then it may impact when we start screening, or when we do preventative surgeries in the future," Litton told MyHealthNewsDaily

This phenomenon "will need to be continued to be tracked through the generations in case we start seeing earlier and earlier ages of onset," Litton said.

The researchers noted their study was small and the participants were from just one hospital. In addition, the study was conducted after participants in the two generations had already developed cancer. Larger studies that follow women forward in time are needed to validate whether anticipation is occurring in breast cancer, Litton said.

BRCA mutations increase the risk of breast and ovarian cancer. Women with a BRCA 1 or 2 mutation have a 60 percent risk of developing breast cancer in their lifetime. The risk for a woman in the general population is 12 percent.

BRCA mutations

The study involved women who were genetically tested and found to have the BRCA 1 or 2 mutation. Each study participant also had a family member who had developed breast or ovarian cancer.

Many of the family members from the older generation were not tested for BRCA mutations (Test for these mutations have only been around 15 years). The researchers analyzed the participants' family trees to determine whether the BRCA mutation seen in the younger generation was inherited though the mother or the father.

The researchers also used a statistical model designed to determine if the anticipation phenomenon is occurring. This model found an eight-year gap between the breast cancer diagnosis of the younger generation and older generation.

Future studies should make sure both generations of women are genetically tested for the BRCA 1 and 2 mutations, Litton said.

The study is published online today (Sept. 12) in the journal Cancer. It was funded by the Nellie B. Connally Breast Cancer Research Fund.

Pass it on: Breast cancer may be showing up at earlier ages in women with a family history of the condition.

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