Oct. 31, 2011— -- Women whose female relatives have a notorious breast cancer gene but who do not have the gene themselves may be able to breathe a slight sigh of relief.
New research that refutes previous findings suggests that women who do not carry their family's BRCA genetic mutation are at no higher risk of getting breast cancer than relatives of people with other types of breast cancer.
The findings of the study, which examined more than 3,000 families, countered a 2007 study that suggested women who tested negative for the BRCA mutation -- but had a first-degree family member who carried the gene -- had a two- to five-fold increased risk of developing breast cancer.
These women still are at greater risk for the disease than women who do not have a family history of breast cancer. But the study's findings, published in the Journal of Clinical Oncology, found that women are not at an even greater risk solely because of their BRCA family history.
"This is a reassuring result," said Dr. Allison Kurian, first author of the study and assistant professor of oncology at Stanford University Medical Center. "We found women who tested negative for BRCA mutation do not have a greatly elevated risk of breast cancer."
"This isn't to say that women may not have other reasons for increased risk due to other factors," said Kurian. "Cases should be managed in an individual way."
Breast cancer is the most common cancer among women in the United States. More than one in eight women will develop the disease in their lifetimes, according to Breastcancer.org. While only about 10 percent of breast cancer diagnoses stem from the genetic mutation, women with the BRCA genetic mutation have a 45 percent to 65 percent chance of getting breast cancer, and those increased odds often result in more frequent mammograms and preventive mastectomies.
The BRCA-1 and BRCA-2 genetic mutations were first discovered in 1994. At the time, researchers believed that relatives of a person who carried the BRCA gene were not at greater risk than any other family member of a person with other kinds of breast cancer. The 2007 study countered that initial belief, but these newly published results bolster the original understanding of the genetic mutation.
"I am really happy to see a relatively large, well done study begin to put an end to this controversy," said Dr. David Euhus, professor of surgical oncology at University of Texas Southwestern Medical Center. "These results make sense. Women from BRCA families who did not inherit the mutation can still get breast cancer, but their risk is no where near as high as their relatives who did inherit the mutation."
The study compared noncarriers with a family BRCA history with noncarriers who have other types of breast cancer in their families.
Kurian said the 2007 study may have found conflicting results because researchers compared the BRCA family members with the general population.
Cancer specialists say patients can now feel some relief and return to normal screening patterns. It's important to educate high-risk patients on appropriate prevention and treatment options, they said..
"Women with a family history of breast cancer are understandably worried about their own risk of developing breast cancer," Dr. Harold Burstein, breast oncologist at Dana-Farber Institute at Boston, wrote in an email. "This study provides strong reassurance that 'no means no' when it comes to negative results on the BRCA1 / BRCA2 genetic tests for these patients. That is, despite the family history, the risk of breast cancer is not greater than that for ordinary women in similar circumstances when the genetic test is 'normal.'"