Family history is considered by many the most important marker for breast cancer risk. Carrying certain genes, like the BRCA1 and BRCA2 genes, puts women at significantly higher risk than women who don’t carry the genes. Now, however, a new study underlines the fact that women without a family history may still be at significant risk for developing the disease, which makes appropriate screening practices all the more important.

. 'All women need to be getting routine screening for this disease regardless of their family history.'

Breast cancer is still the second leading cause of cancers in women, following only lung cancer, according to background information in the study. Approximately 192,000 women were diagnosed with breast cancer in 2009, and 40,000 women die from it every year.

The authors report that according to the literature, many doctors only consider a woman’s family history, and fail to ask women about other important factors, like the age at which her period began (menarche), how many children she’s had, and whether she’s had previous biopsies. The team says that if doctors use only family history, women without a family history who are at high risk because of other significant markers may be slipping under the radar.

In the current study, the authors looked at the risk factors in over 6,000 women who had taken part in earlier research studies. A program called the Breast Cancer Risk Assessment tool (BCRA) was used to look retrospectively at the women’s risk levels, and to determine, based on who developed breast cancer during the study period, each woman’s relative risk for the disease.

More than half of the women in the study fell into the "high risk" category, even though they didn’t have a family history. As expected, having a family history doubled a woman’s risk. However, the majority of women who went on to develop breast cancer did not have a family history.

Lead author Larry Wickerham, MD told TheDoctor that "Of the more than 200,000 women in the United States who developed an invasive breast cancer last year, 70%+ did not have a family history. This paper reconfirms that fact with more than twice as many breast cancers occurring in women with no family history. One take home message is that all women need to be getting routine screening for this disease regardless of their family history."

Wickerham also tells us that the BCRA tool used in the study "is on-line at the [National Cancer Institute] web-site and can help health care providers to identify a larger group of women at increased risk to target for additional emphasis for screening and for discussions concerning approved therapies to reduce their risk." He also underlines that the most important markers for breast cancer risk are "current age, age at first menstrual period, reproductive history, previous benign breast biopsy information and race."

The study comes a time where breast screening practices are under hot debate in this country, with the American Cancer Society recommending all women above 40 be screened, and United States Preventive Services Task Force recommending that it not begin till age 50. The authors urge that clinicians to take the current findings into account as they reconsider their screening practices in the future. As Wickerham says, "[t]he single largest risk factor for developing a breast cancer is being a women and the second largest is being a women over 50. This is why we screen ALL women for the disease using regular physical exams and mammograms."

The study was executed by researchers at Eli Lilly and the National Surgical Adjuvant Breast and Bowel Project (NSABP), and published in the December 25, 2010 issue of Menopause. Special thanks to Dr. Wicherham, NSABP Operations Chair, for speaking with TheDoctor.