Most women don’t know their own breast cancer risk

Most women do not have an accurate understanding of their breast cancer risk — a finding that has important implications for prevention and early detection, as well as psychological well-being, according to a survey of nearly 10,000 women undergoing mammography screening.

When asked to estimate their lifetime personal breast cancer risk, just 9.4 percent of the women gave a value that was within 10% of their actual calculated risk, according to data reported in a press briefing held in advance of the breast cancer symposium sponsored by the American Society of Clinical Oncology.

“Despite all the ongoing media attention, awareness campaigns, pink ribbons, breast cancer walks, and breast cancer month, most women lack accurate knowledge of their own breast cancer risk.”

“We began to think: What happens to women when they underestimate their risk of breast cancer? Well, they probably don’t get necessary of most accurate treatment.” In particular, this group could benefit from a tailored plan of chemo prevention and early detection.

In the study, the investigators surveyed 9,873 women aged 35-70 years who were about to undergo screening at 21 Long Island mammography centers. The anonymous questionnaire included many questions adapted from National Cancer Institute’s Breast Cancer Risk Assessment Tool.

The women’s subjective estimate of risk was compared with their risk as calculated with the tool. Their estimated was considered inaccurate if it differed from their calculated risk by more than 10 percent.

Most of the women were at average calculated risk, with 35 percent having a 5 percent -10 percent lifetime risk and 40 percenthaving 10 percent-15 percent lifetime risk.

Just 9.4 percent of the women, however, accurately estimated their risk, while 46 percent overestimated and 45 percent underestimated.

The predominant direction of estimation error varied by race/ethnicity. Of the white women, 10 percent accurately estimated their risk, 39 percent underestimated, and 51  percent overestimated their risk.

Women of other ethnicities were more likely to underestimate their breast cancer risks. Just 9 percent of African American women in line with their risk, with 58 percent underestimating and 34 percent overestimating. Asian women had similar assessments. Hispanic women’s inaccurate assessments were more balanced, with 50 percent understimating and 41  percent overestimating risk. Although these differences were statistically significant, it is more important to note that the overall level of understanding was very low.

Ideally, patients should learn of their breasts cancer risk from their physician, but the study data told another story. “All of these women were about to have mammography, so they obviously had some interest in their breast health,” but when asked when they last spoke to their doctor about their personal breast cancer risks, “were shocked to find that 40 percent of women said they never ever had a conversation with a health care provider.”

The findings suggests a need to improve communication about risk by primary care providers, especially the US Preventive Services Task Force is now putting greater emphasis on informed decision making.

But patients could be spurred to action as well, by moving beyond the pink ribbons and asking their physician, “what are my breast cancer numbers? I need to know that.”