Most Women Wrongly Estimate Their Risk for Breast Cancer

Zosia Chustecka

September 04, 2013

Despite the huge amount of publicity given to breast cancer with pink ribbons and other campaigns, many women wrongly estimate their own risk of developing the disease.

Results from a large survey, released today, show that only 1 in 10 women has a good idea of her lifetime risk for breast cancer.

Researchers conducted a survey of 9873 women who attended a screening clinic in Long Island, New Jersey, to undergo mammography.

Of the 90% of women who wrongly estimated their risk of developing breast cancer, about half underestimated their risk and about half overestimated it.

In addition, 40% of the women had never discussed their personal risk for the disease with their doctor.

These results suggest that "our education messaging is far off and that we should change the way that breast cancer awareness is presented," said lead researcher Jonathan Herman, MD, an obstetrician and gynecologist at Hofstra North Shore–LIJ Medical School in New Hyde Park, New York.

Without a formal estimation, a woman will "just be guessing at her risk," he noted.

Dr. Herman was speaking at a presscast in advance of the 2013 Breast Cancer Symposium, which will be held in San Francisco. The presscast was organized by the American Society of Clinical Oncology (ASCO), which, along with 5 other professional bodies, is sponsoring the symposium.

"This is a provocative and I think compelling study," said presscast moderator Steven O'Day, MD, who is an ASCO spokesperson. It shows how much more work is needed to improve communication between women and their doctors. "It's information like this that sets the record straight on just how far we have to go," he explained.

Surprise at How Many Women Didn't Know

Dr. Herman said he was surprised by the findings. Before the survey, he would have guessed that about 25% to 50% of women would know their life-time risk of developing breast cancer, especially women who were about to undergo a mammography and who presumably had some interest in their breast health. He speculated that knowledge about breast cancer risk might be even lower in the general population.

"Despite all the pink ribbons, marches, and awareness, it is disconcerting that only 9.4% of women could tell us their breast cancer risk," he said.

He was also shocked to find that so many of these women (40%) who were undergoing mammography had never discussed their breast cancer risk with their doctor.

Dr. Herman said he plans to do a survey of family practitioners, who are supposed to be talking to their patients about breast cancer risk, especially those undergoing mammography.

The US Preventative Services Task Force recommends in its guidelines on mammography that doctors discuss breast cancer risk with women, "but it's our feeling that the primary family care physicians are not doing this, and your paper proves it," said William R. Poller, MD, FACR, from the National Consortium of Breast Centers. He is associate director of radiology at Drexel University and associate director of the Breast Care Center at Allegheny General Hospital in Pittsburgh, and will be moderating the session when the survey results are presented at the symposium.

Breast cancer assessment risks are available free online, and going through the questions only "takes a minute," Dr. Herman noted. "But that minute is not being spent often enough in doctors' offices."

"Women should be aware of their breast cancer risk number, just as they know their blood pressure, cholesterol, and body mass index," he said in a statement.

Women Could Be Missing Out

The fact that 45% of the women surveyed underestimated their risk for breast cancer means that some women are likely missing out on additional surveillance with MRI and chemoprevention with drugs such as tamoxifen and raloxifene, Dr. Herman said.

There is a risk here that some of these women are being undertreated, Dr. O'Day added.

Conversely, the 45% who overestimated their risk for breast cancer are "worrying more than they really have to." The risks here are of overtreatment, too much screening, and possibly psychological harm from anxiety, Dr. O'Day explained.

When the researchers parsed the results by ethnicity, they found that white women were more likely to overestimate their risk for breast cancer, whereas black, Asian, and Hispanic women were more likely to underestimate their risk. But across the board, knowledge was low," Dr. Herman emphasized.

To analyze the survey results, a woman's subjective view of her risk of ever developing breast cancer was compared with her actual lifetime risk, which was calculated using the National Cancer Institute's Breast Cancer Risk Assessment Tool. If there was more than a 10% discrepancy between the 2, the woman's estimate was considered to be wrong.

"We found a good spread among the women surveyed," Dr. Herman reported. Most women were at average risk, but there were some at very high risk for breast cancer and some at very low risk.

It is the women at a greatly increased risk for breast cancer who stand to benefit from this knowledge, he explained. They are the ones who could benefit from extra surveillance and/or chemoprevention.

Decisions about strategies of extra surveillance and chemoprevention are difficult to make when the risks are known, added Dr. O'Day, but they are "almost impossible" to make without an appreciation of the actual breast cancer risk.

Dr. Herman has disclosed no relevant financial relationships. Dr. O'Day reports acting as consultant or advisor for Bristol-Myers Squibb, Delcath, Eisai, Genentech, GlaxoSmithKline, and Roche; accepting honoraria from Bristol-Myers Squibb, and receiving research funding from Bristol-Myers Squibb, Eisai, GlaxoSmithKline, Lilly, and Roche/Genentech.

2013 Breast Cancer Symposium: Abstract 4. To be presented September 7, 2103.


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