HRT Trial Stopped in Women with Breast Cancer
February 3, 2004 A Swedish study designed to assess the effect of hormone replacement therapy (HRT) in women who have had breast cancer has been stopped early after preliminary results found an "unacceptably high" risk of breast cancer recurrence in the women who used HRT. The results were published online in the Lancet on February 2, 2004.
The question of whether women who have had breast cancer should take HRT to help control menopausal symptoms has been controversial for many years. Small observational studies (studies that looked at women who had breast cancer who had taken HRT) found the risk of breast cancer to be low. But observational findings must always be tested, which is why researchers designed randomized trials to look at the impact of HRT in women who have had breast cancer.
The study published in the Lancet was called HABITS (hormonal replacement therapy after breast cancer—is it safe?). The trial began recruiting women in 1997 to determine whether a two-year treatment of HRT for menopausal symptoms was safe for women who had had breast cancer. All of the women in the study had completed chemotherapy and radiation treatment for up to Stage II breast cancer, although some were still taking tamoxifen.
The study followed 345 women; 174 were randomized to HRT while the other 171 did not receive HRT. After following the women for about two years, 26 women in the HRT group had a new breast cancer occurrence compared with 7 in the non-HRT group.
In the HRT group, 11 women experienced a local recurrence, 5 developed cancer in the opposite breast, and 10 were diagnosed with distant metastases. All but five of the women had their new diagnosis occur while they were taking HRT. In the non-HRT group, two had a local recurrence, one developed cancer in the opposite breast, and five were diagnosed with distant metastases.
Five women in the HRT group died (three due to breast cancer) and four died in the non-HRT group (all due to breast cancer).
In an accompanying commentary, Rowan T. Chlebowski, MD, chief of the Division of Medical Oncology and Hematology at Harbor-UCLA Medical Center, and Nananda Col, MD, an assistant professor of medicine at Brigham and Women's Hospital, note that "although the HABITS trial may not be the definitive word on the use of hormone therapy in breast cancer, it will probably be the last word when considered in context of our evolving understanding of the effects of hormone therapy on chronic disease in women."
They add: "The HABITS investigators' conclusion that even short-term use of hormone therapy poses an unacceptably high risk of breast cancer can now reasonably guide clinical practice for women with breast cancer."
Susan says:
We have long felt that women who have already had breast cancer would increase their risk of a recurrence of the original cancer or of a second breast cancer if they used HRT—and the results of the HABITS study bear this out.
This makes sense, since part of the treatment of breast cancer is blocking estrogen either by tamoxifen or with one of the new aromatase inhibitors. In other words: Why would you give the hormone estrogen to a group of women whose treatment includes reducing the estrogen they are exposed to?
The non-randomized, observational studies that showed that giving HRT might be safe were always hard to evaluate because those women who were offered HRT were those who had a low risk for recurrence. That's one reason why the findings from this randomized study carry more weight.
The findings from this study support my belief that HRT for women who have had breast cancer is a bad idea. Any woman who has had cancer is at risk of having a recurrence or a second cancer, or of developing breast cancer in the opposite breast. And while I understand why a woman with severe menopausal symptoms may want to take HRT, for women with breast cancer, the risks outweigh the benefits.
If you have had breast cancer and are experiencing severe menopausal symptoms, I would encourage you to try some of the alternative treatments that are out there. You can read more about them here.
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