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Study finds disparities in women’s knowledge about their own breast cancer

Image: National Cancer Institute/Bruce Wetzel and Harry Schaefer

A new study from Harvard Medical School and Dana-Farber Cancer Institute found a surprising lack of knowledge among breast cancer patients about the basic characteristics of their disease— how advanced it is (stage), whether it is fueled by estrogen, whether it can be treated with trastuzumab (Herceptin) and the grade assigned by pathologists.

All these factors are taken into account when treatments are recommended for women, and the researchers suggest that patients who fully understand their cancer may be more likely to adhere to their treatment regimens.

Women from minority groups in the diverse population of patients studied were less likely than white women to know this information, according to the findings reported online in Cancer, a peer-reviewed journal of the American Cancer Society.

“We were really surprised by the results,” said Rachel Freedman, HMS assistant professor of medicine and medical oncologist in the Susan F. Smith Center for Women’s Cancers at Dana-Farber, who is first author of the report. Nancy Keating, HMS professor of health care policy and assistant professor of medicine at Brigham and Women’s Hospital, is senior author.

The study is believed to be the first to pose these questions, said Freedman, who proposed the research after discovering in her own practice that many women did not understand the reasons for the specific treatments they were receiving. This discrepancy, which she described as astounding, also emerged in focus group sessions. Although past research has examined a patient’s general cancer knowledge with regard to basic treatment rationales and reasons for screening, this is the first study to examine how much women know about their own cancers. Rachel Freedman. Image: Sam Ogden

Telephone interviews were carried out with 500 women in the California Cancer Registry who had undergone surgery for breast cancer. They were asked what the stage of their cancer was (0 through 4); whether it was low, intermediate or high grade; whether it was HER2 (human epidermal growth factor receptor-2) positive (generally treated with trastuzumab); and whether it was ER (estrogen-receptor) positive. The researchers then compared the answers with the data from the California Cancer Registry.

The results: 33 percent reported knowing their disease stage; 32 percent said they knew the grade of their tumor; 55 percent of women said they knew whether it was HER2- or ER-positive. Thirteen percent of respondents said they knew all four characteristics, while 14 percent reported knowing none of them.

In reality, the researchers determined 57 percent of women were correct about the cancer’s stage, 20 percent reported the correct grade, 58 percent reported the correct HER2 status, and 56 percent were correct on their ER status. Only 8 percent of women surveyed were correct on all four questions.

Women who self-identified as Hispanic or black had less knowledge about their tumors. Less knowledge was also associated with having less formal education and lower health literacy.

“Of all of these factors, a tumor’s grade is likely the least important element for patients to know, although physicians use grade to make decisions about treatments, including chemotherapy,” Freedman said.

Knowing the stage is more important, she said, because it is a measure of the patient’s risk, and knowing the cancer’s HER2 status could help patients with HER2-positive tumors understand why they need to take trastuzumab for a year. Patients with ER-positive breast cancers often take tamoxifen or aromatase inhibitors for many years, so that knowledge might motivate such women to stick to the regimen.

Freedman believes that patients’ knowledge of their cancer “has to be a good thing” and plans to look for evidence on that point in further research.

The research was supported by the Susan G. Komen Foundation.

Adapted from a Dana-Farber news release.