HRT Hampers Accuracy Of Breast Cancer Tests, New Analysis Says

Main Category: Breast Cancer
Also Included In: Endocrinology;  Seniors / Aging;  Women's Health / Gynecology
Article Date: 28 Feb 2008 - 7:00 PST

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Postmenopausal women taking combined hormone replacement therapy have only a slightly higher risk of developing breast cancer, but there are much greater chances they will experience the worry of abnormal mammograms or undergo an avoidable breast biopsy than postmenopausal women not taking the drugs, according to a study published Monday, the San Francisco Chronicle reports. In addition, the tools used to diagnose breast cancer are less likely to catch malignant tumors in women taking combined HRT, despite the slightly increased risk of cancer, according to the study. Although the findings are "another small mark" against HRT, physicians said the study should not stop women from taking the drugs to alleviate menopausal and postmenopausal symptoms, especially if the symptoms are severe, the Chronicle reports (Allday, San Francisco Chronicle, 2/26).

For the study, Rowan Chlebowski, an investigator with the Los Angeles Biomedical Research Institute, and colleagues analyzed data from about 16,600 postmenopausal women who participated in the NIH-sponsored Women's Health Initiative (Houston, Irish Times, 2/26). NIH researchers ended the WHI study of combination HRT three years early in July 2002 because they determined that the treatment might increase the risk for heart disease, invasive breast cancer and other health problems (Daily Women's Health Policy Report, 10/10/07).

According to Reuters, Chlebowski and colleagues' analysis confirmed initial WHI findings that HRT use led to about one additional breast cancer case per 1,000 women, compared with women not taking HRT. Doctors identified 199 breast cancer tumors in the HRT group and 150 in the placebo group during the five-and-a-half year study.

Although the analysis does confirm a small increase in the risk of breast cancer, Chlebowski said the more important findings were that about one in 10 women taking HRT had a mammogram abnormality that would not have otherwise have been present and that one in 25 women taking HRT had an "otherwise avoidable" breast biopsy. The analysis, published in the Archives of Internal Medicine, found that 35% of women on HRT had mammogram abnormalities, compared with 23% of women taking a placebo. About 10% of women taking HRT were ordered by their doctors to undergo a breast biopsy, compared with 6% in the placebo group (Stern, Reuters, 2/25). About 15% of biopsies on women taking HRT identified malignant tumors, compared with 20% of biopsies among women not on HRT.

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According to the Chronicle, researchers do not know why women taking HRT have a higher rate of mammogram abnormalities but suspect it is because many of them develop denser breast tissue. Many studies have shown that mammograms are less likely to detect tumors in dense breast tissue (San Francisco Chronicle, 2/26).

Chlebowski said postmenopausal women who are considering hormone therapy should "take the results of this study into consideration and consult with their physicians before undergoing even short-term hormone therapy." He also noted that one year after discontinuation of HRT, the "adverse effects on mammogram and breast biopsy performance were seen even in younger women in the fifth decade of life, so the finding may impact women just entering menopause as well" (Reuters, 2/25).

Susan Kutner -- a surgeon at Kaiser Permanente Santa Teresa Medical Center in San Jose, Calif., who chairs Kaiser's Regional Breast Care Task Force -- said women on HRT also need to think about the psychological impact of a breast biopsy or abnormal mammogram results. According to Kutner, breast biopsies are relatively painless and physically uncomplicated, "but psychologically, it's a big deal for a woman to be told that there's something abnormal." She added, "It would be wonderful if we could develop some other therapies that don't have terrible side effects and are just as effective" (San Francisco Chronicle, 2/26).

An abstract of the study is available online.

NBC's "Nightly News" on Monday reported on the study. The segment includes comments from Chlebowski and breast cancer expert Susan Love (Snyderman, "Nightly News," NBC, 2/25). Video of the segment is available online.

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