- Women who have a family history are more likely to develop breast cancer later in life
- Older women with family history have a two-fold increased risk of breast cancer than women with no family history
- Mammography screening is recommended every two years for women who are between 50 and 74 years
Women with family history of breast cancer are at a higher risk of developing invasive breast cancer as they age, especially when they are 65 years and older.
The results of this study can impact mammography screening decisions later in life. The study was published in JAMA Internal Medicine.
‘Older women who are in good health and have a first-degree family history need to screen mammogram as they age, even after 74 years.’
Family History: Major Risk Factor for Breast Cancer
This is the first extensive study where more than 400,000 women who are in the age group of 65 to 74 and 75 and older were included in the study. Family history as a breast cancer risk factor was analyzed in both the groups.
The research team was led by Dejana Braithwaite, Ph.D., who is an associate professor of oncology at Georgetown University School of Medicine and a member of Georgetown Lombardi Comprehensive Cancer Center.
"Family history of breast cancer does not decline as a breast cancer risk factor as a woman ages. The relationship didn't vary based on whether a first-degree relative's diagnosis was made in a woman age 50 or younger, or older than age 50. This means that women with that first-degree family history breast cancer in a mother, sister, or daughter should consider this risk factor when deciding whether to continue mammography screening as they age," said Braithwaite.
Importance of Screening Mammography
Currently, mammography screening is recommended every two years for women who are between 50 and 74 years, and also for women at average risk, reveals the U.S. Preventive Services Task Force (USPSTF).
The evidence for those who are above 75 years is insufficient to assess risk and benefit of mammography, revealed USPSTF's in 2016.
Yearly mammograms are recommended for women who are aged 45 years, and then biennial screening at 55 years, until a woman is in good health, according to the American Cancer Society.
"As breast cancer screening guidelines change from age-based to risk-based, it is important to know how standard risk factors impact breast cancer risk for women of different ages," said Karla Kerlikowske, MD, senior author of the new study and a member of the UC San Francisco Helen Diller Family Comprehensive Cancer Center.
Braithwaite said that their goal is to provide evidence that helps inform screening guidelines for breast cancer in older women.
Senior women who are in good health and have a first-degree family history need to screen mammogram as they age beyond the screening recommendations for average-risk women.
The research teams who participated in this study were from Washington, California, Wisconsin, Vermont, New Hampshire and North Carolina. They examined records from the Breast Cancer Surveillance Consortiums (BCSC) registries in their regions from 1996-2012.
Older Women at Risk of Breast Cancer
The research team found that age is the most influential risk factor for breast cancer. Any adult woman in the general population has a baseline 12 percent risk of developing breast cancer, where first-degree family history can double that risk.
Overall, a first-degree family history leads to an absolute increase in the 5-year risk of breast cancer ranging from 1.2 to 10.3 percentage points depending on breast density and age.
For example, women who are between 65-74 years with separate areas of dense tissue in their breasts had an increased 5-year risk of breast cancer, ranging from 15.1 percent in women without a family history of breast cancer to 23.8 percent in women whose first-degree female relatives had developed the disease.
Likewise, women who were 75 years or older with the same scattered breast density, their 5-year cumulative risk of breast cancer was found to be increased from 15.9 percent for women without a family history to 23.1 percent for women with a family history.
The research team also discovered that breast density did not attenuate the association of family history of breast cancer and the risk of breast cancer in the women when studied as a whole.
However, when broken into different age groups, fatty breasts added a little risk to women who are in the age group of 65-74 years with a family history; and in the older cohort, the association was flipped dense breasts added slight risk.