Experts Offer Better Means of Gauging Breast Cancer Risk

TUESDAY, June 19 (HealthDay News) -- Current methods of gauging a woman's breast cancer risk that rely on her family history may often underestimate the danger, a new study suggests.

These risk models help determine if a woman might carry theBRCA1orBRCA2gene mutations that would predispose her to the disease, the research team explained. If her family history suggests she might carry such a gene, she might be offered a test to screen for the mutations.

But the new study, published in the June 20 issue of theJournal of the American Medical Association, found that there may be a better way to refine the risk model so those predictions are more accurate.

"In some circumstances, we have to qualify what family history can tell us," explained lead researcher Dr. Jeffrey Weitzel, director of the department of clinical cancer genetics at City of Hope Comprehensive Cancer Center in Duarte, Calif. He pointed out that family history data isn't always available to women, and "if there's no family, then you can't have a family history, if you don't have older women in either lineage."

"We're trying to predict which women should get tested [for a genetic predisposition]. The test is expensive, and not every woman can get it," added Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La. However, "with smaller families today, many times you don't have that extensive family tree that you can reconstruct," said Brooks, who was not involved in the study.

The implications could be lifesaving for many women. Mutations inBRCA 1andBRCA 2, especially, can greatly increase a woman's risk of developing both breast and ovarian cancer.

"It's now medically necessary that access to care should be broader, and more people should be able to take advantage of [gene screening], because it may make a big difference in outcome," Weitzel said. "Failure to recognize that a woman happens to be aBRCAcarrier and do appropriate prevention procedures could cost a woman her life."

AlthoughBRCAmutations are relatively rare (affecting only about 5 percent of the population), those with the misfortune to carry them have a 50 percent to 85 percent greater chance of developing breast cancer and a 16 percent to 50 percent higher risk of developing ovarian cancer.

Women with breast cancer who have aBRCAmutation also have a higher risk of developing another breast cancer or ovarian cancer. A mastectomy or oophorectomy (removal of the ovaries) can significantly reduce that risk.

Most of the methods available to estimate how likely a person is to carry theBRCA 1orBRCA 2defects were developed using data from large families. They incorporate information on family history, age at diagnosis and ethnic ancestry.

It is these models that are most often used by insurance companies when deciding whether or not to pay for the gene test.

But the fact that a woman's father might have passed on the mutation is often not taken into account, Weitzel noted. "Half of all heredity for breast cancer comes from dad," he said. "Most clinicians don't realize thatBRCAcan be inherited through dad."