New Breast Cancer Risk Found With Hormone Replacement Therapy
The risks were also calculated by each increasing year of use. Women on estrogen alone had an increased risk of 1% a year for each year of use, compared with women on the estrogen-progestin combination, for whom the increase was 8% a year. The ill effects were seen most in women with long-term use, and the increased risk seemed to disappear within four years after HRT has been stopped.
Lead author Catherine Schairer, PhD, an epidemiologist with the National Cancer Institute, tells WebMD she does not support completely abandoning long-term HRT based on her research. "I think one study is never definitive. There need to be other studies confirming these results. On the other hand, I feel reasonably confident of my results. I think a woman may still consider the use of estrogen alone if she has a uterus. If a woman still feels she wants HRT, she should be carefully monitored. She should at least get what is recommended in terms mammograms and clinical exams."
While Walter Willett, MD, DrPH, and his colleagues at the department of epidemiology and nutrition at the Harvard School of Public Health call "strong" the "evidence that the addition of progestin to estrogen increases the risk of breast cancer," they write in an accompanying editorial that the cause-and-effect remains unproven. Still, they urge a pointed review of the reasons why menopausal women would be placed on hormone therapy, and they admonish clinicians and patients for overlooking lifestyle interventions.
Felicia Cosman, MD, urges a measured response to the research.
"I think it would be a mistake for women who are taking estrogen to stop taking it based on this study," Cosman says. "Women should not indiscriminately go on estrogen because they go through menopause. If they and their doctors feel that the heart disease data and the osteoporosis data and the preventive effects for Alzheimer's disease data are strong, and they have a history of those diseases, then I think it is reasonable" to be on HRT long-term. Cosman, who is clinical director for the National Osteoporosis Foundation and an endocrinologist and director of osteoporosis programs at Helen Hayes Hospital in New York, reviewed the study for WebMD.