The use of hormone therapy may affect the ability of both mammography and breast biopsies to accurately diagnose breast cancer. These results were recently published in the Archives of Internal Medicine.
Postmenopausal hormone therapy with the female hormones estrogen alone or estrogen plus progestin (combined hormone therapy) effectively manages several common menopausal symptoms. However, large clinical trials conducted as part of the Women’s Health Initiative (WHI) raised concerns about the health risks of these therapies. In 2002, for example, it was reported that combined estrogen plus progestin increases the risk of breast cancer, heart disease, stroke, and blood clots. Women taking estrogen plus progestin had fewer fractures and were less likely to develop colorectal cancer, but for most women, these benefits were thought to be outweighed by the risks. Although hormone therapy increases the risk of breast cancer (see first article in related news), it is not clear how it effects detection of breast cancer.
Researchers affiliated with the WHI recently evaluated data from the WHI trial to determine if hormone therapy affected the accuracy of diagnosis of breast cancer. The WHI trial included more than 16,000 postmenopausal women who were treated either with combined hormone therapy or placebo (inactive substitute). Data evaluated included mammography and breast examinations that were performed when the trial began and annually throughout the trial. Breast biopsies (removal of a sample of tissue for microscopic evaluation) were performed if there a suspicious area was found on mammography or clinical exam.
- More mammograms in the group of women treated with hormone therapy revealed abnormalities compared with mammograms in the group of women who received placebo (35% versus 23%).
- 10% of women with abnormal mammograms received subsequent biopsies compared with 6% of women in the placebo group.
- Although the rate of breast cancer was higher among women treated with hormone therapy, biopsies diagnosed cancer with less frequency in this group of patients compared with those who received placebo.
- In five years 10% of women had abnormalities found on mammography, while 4% underwent unnecessary biopsies that were directly attributable to hormone therapy.
The researchers concluded: “This adverse effect on breast cancer detection should be incorporated into risk–benefit discussions with women considering even short-term combined hormone therapy.” Postmenopausal women on hormone therapy may wish to discuss screening measures with their physician.
Reference: Chlebowski T, Anderson G, Pettinger M, et al. Estrogen plus progestin and breast cancer detection by means of mammography and breast biopsy. Archives of Internal Medicine. 2008;168:370-377.