Despite taking a tailored risk assessment tool that factors in family history and personal habits, nearly 20 percent of women did not believe their breast cancer risk, according to a new study from the University of Michigan Comprehensive Cancer Center.

Most of the women who didn’t believe their risk numbers said they did not feel it took into account their family history of cancer or their personal health habits. The tool did ask relevant questions about the individual’s family and personal history.

“If people don’t believe their risk numbers, it does not allow them to make informed medical decisions,” says senior study author Angela Fagerlin, Ph.D., associate professor of internal medicine at the University of Michigan Medical School and a research scientist at the VA Ann Arbor Center for Clinical Management Research.

“Women who believe their risk is not high might skip chemoprevention strategies that could significantly reduce their risk. And women who think their risk should be higher could potentially undergo treatments that might not be medically appropriate, which can have long-term ramifications,” she adds

The findings, published in Patient Education and Counseling, are part of a larger study looking at how to improve patients’ understanding of risk information.

Some 690 women who were at above-average risk of developing breast cancer completed a web-based decision aid that included questions about age, ethnicity, personal history of breast cancer, and number of first-degree relatives who had had breast cancer. The women then were told their five-year risk of developing breast cancer and given information about prevention strategies.

After receiving this information, the women were asked to recall their risk of breast cancer within the next five years. If they answered incorrectly, they were asked why: they forgot, made a rounding error or disagreed with the number. The researchers found that 22 percent of women who misreported their risk said they disagreed with the numbers.

The most common reason women said they disagreed with their risk was that their family history made them either more or less likely to develop breast cancer. Many believed that because an aunt or father had cancer, it increased their risk. Only first-degree female relatives—mother, sister, daughter – impact a person’s breast cancer risk. Others felt a lack of family history meant their cancer risk should be very low.

One-third of women cited a gut instinct that their risk numbers just seemed too high or too low. 

“We’ve put so much fear in people about breast cancer so they feel at high risk,” says lead study author Laura D. Scherer, Ph.D. “We found that many women assumed certain factors should impact their risk, like cancer history in distant or male relatives, but those factors don’t put a woman at increased risk.

“We have a trend toward personalized medicine and individualized medicine, but if people don’t believe their personalized risk numbers, they’re not going to get the best medical care for them,” says Scherer, who is now at the University of Missouri. She completed the research while at the University of Michigan.

Breast cancer statistics: 234,580 Americans will be diagnosed with breast cancer this year and 40,030 will die from the disease, according to the American Cancer Society

Additional authors: Peter A. Ubel, Duke University; Jennifer McClure, Group Health Research Institute; Sharon Hensley Alford, Henry Ford Health System; Lisa Holtzman, University of Michigan; Nicole Exe, University of Michigan

Reference: Patient Education and Counseling, Vol. 92, No. 2, pp. 253-259, August 2013

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