New study says family history increases breast-cancer risk, even among older women. US mammogram guidelines need updating–soon.

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The News:

Women are more likely to develop breast cancer when a mother or sister had this disease, and the risk associated with family history doesn’t diminish regardless of age, a US study suggests.

Family history has long been linked to a higher risk of breast cancer in younger women, who are generally advised to start getting screening mammograms when they’re ten years younger than the age their relative was at diagnosis. But family history has been thought to be less of a factor for the elderly, and women often stop routine screenings by their 70s, Reuters notes.

“Older women with family history have an approximately two-fold higher risk of breast cancer compared to women with no family history,” said lead study author Dejana Braithwaite, PhD, of the Lombardi Comprehensive Cancer Center at Georgetown University Medical Center in Washington, DC.

“As we go from age-based to risk-based screening recommendations, our findings show that older women with family history may benefit from continued mammography screening, even after age 74,” Braithwaite said.

While current US guidelines advise women to get a screening mammogram every other year from age 50 to 74, the US Preventive Services Task Force (USPSTF) hasn’t found sufficient evidence yet to weigh in on whether women should continue screening after that.

Obviously, the goal of mammograms is to detect tumors before they can be felt in a physical breast exam, catching cancer sooner when it’s easier to treat. Ideally, this should mean fewer women are diagnosed when tumors are bigger, rapidly growing, and harder to attack.

Concerns have centered on how widespread screening can also catch small, slow-growing tumors that are unlikely to be fatal. Particularly when women are older or have a limited life expectancy, detection of these less dangerous tumors might result in needless tests and treatment.

But for older women with a family history of breast cancer, the benefits of screening may still outweigh the risks.

Researchers examined data on 403,268 women ages 65 or older, including 10,929 who developed breast cancer during an average follow-up period of 6.3 years. When women ages 65 to 74 had a family history, they were 48% more likely to develop breast cancer, the study found. For women 75 or older with a family history, the increased risk was 44%.

Overall, the elevated risk associated with family history didn’t appear to vary based on the relative’s age when diagnosed with breast cancer. Among women ages 65 to 74, the risk tied to family history was highest for people with fatty breast tissue, researchers note in JAMA Internal Medicine. After 75, however, the risk linked to family history was greatest for people with dense breasts.

Steve’s Take:

A study such as this Georgetown-led research exemplifies the importance of the widest possible dissemination of its findings because government guidelines need crucial updating that certainly will result in the saving of lives. We’re talking about lives that otherwise wouldn’t be spared because the guidelines are simply outdated.

Steve's Take: New study shows that women with family history of #breastcancer have an elevated risk regardless of age Click To Tweet

So let’s briefly focus on the highlights of this life-saving study with the hope that word-of-mouth dissemination of its findings is facilitated.

“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,” says Dejana Braithwaite, PhD, associate professor of oncology at Georgetown University School of Medicine and a member of Georgetown Lombardi Comprehensive Cancer Center.

“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,” Braithwaite said.

The American Cancer Society recommends yearly mammograms in women age 45, and then biennial screening at age 55 and on “as long as a woman is in good health.” And currently, the US Preventive Services Task Force (USPSTF) recommends mammography screening every two years between ages 50 and 74 for women at average risk. After age 75, the evidence is insufficient to assess risk and benefit of mammography, according to USPSTF’s most recent update in 2016.

But that’s not true any longer.

“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.

“The goal of our work is to provide evidence that helps inform breast cancer screening guidelines for older women,” Braithwaite says. “Older women who are in good health and have a first-degree family history may consider a screening mammogram even as they age beyond the screening recommendations for average risk women.”

Researchers from Washington, California, Wisconsin, Vermont, New Hampshire and North Carolina participated in the research by examining 1996-2012 records from the Breast Cancer Surveillance Consortiums (BCSC) registries in their regions.

The team found that while age is the strongest risk factor for breast cancer–any adult woman in the general population has a baseline 12% risk of developing the disease–first-degree family history can almost double that risk, according to Science Newsline.

Overall, a first-degree family history leads to an absolute increase in 5-year risk of breast cancer ranging from 1.2 to 10.3 percentage points depending on breast density and age.

For example, in women 65-74 years old with scattered areas of dense tissue in their breasts, the team found an increased 5-year risk of breast cancer that ranged from 15.1% in women without a family history of the disease to 23.8% in women whose first-degree female relatives had developed breast cancer.

Similarly, among women 75 years or older with the same scattered breast density, 5-year cumulative risk of breast cancer increased from 15.9% for women without a family history to 23.1% for women with a family history.

Bottom Line:

The results of the Georgetown study are consistent with previous research, the authors noted, such as a 2004 study by Sweeney et al that found that women ages 75 and older had a hazard ratio for cancer of 1.54 if they had a first-degree relative with cancer.

On the other hand, the risk level reported in the new study was lower than in several other studies; however, the other studies included younger women, as well as women who were screened outside the US.

Braithwaite previously led a literature review that found evidence to support the benefits of mammography screening for women ages 65 and older. Indeed, in the current paper, the authors wrote that advancing age is a major risk factor for breast cancer, with risk peaking between the ages of 75 and 79.

Crucially, Braithwaite and colleagues found that the cohort of women ages 75 and older had the highest prevalence of family history of cancer in their study. They advised that older women continue to consider mammography screening as they reach the upper limits of the USPSTF guidelines.

“Providers should continue to ask older women about family history of breast cancer to personalize mammography screening strategies,” the group concluded. “Crucially, family history needs to be taken into account when considering the potential benefits versus harms of continued mammography in this population.”

Now, go out and, when appropriate, mention this Georgetown study to relatives, friends and associates who are “older” women (or otherwise connected to this cohort), who just may thank you one day for saving their life.

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