Evidence Lacking for HRT-Breast Cancer Link
Researchers took fresh look at three large studies, concluded data wasn't convincing
The new conclusion drew mixed reactions from experts.
In an editorial accompanying the study, Nick Panay, a consultant gynecologist at the Queen Charlotte's & Chelsea Hospital in London, supported the conclusions of the new analysis. "If there is a risk, the risk is small, and the benefits of HRT can be life-altering," he wrote. "It is vital that we keep this in perspective when counseling our patients."
The hormone therapy in use today, Panay said, is lower in dose than those used in the previous research. "In principle, we tend to start with lower doses than we used to and increase as required until full symptom relief has been achieved," he said.
What is needed now, he said, is a clinical trial in which the hormone therapy in use today is compared with placebo, to evaluate the risks and benefits.
Another expert took a more middle-of-the-road view about the potential link.
"It would be hard to say the entire decline [in breast cancer rates] is due to the decline in HRT use," said Dr. Steven Narod, the Canada Research Chair in Breast Cancer at the University of Toronto.
According to Dr. Susan Gapstur, vice president of epidemiology for the American Cancer Society, the new analysis overlooks some other important information. "Indeed, there is a much larger body of scientific evidence from clinical trials and from observational epidemiologic studies comparing breast cancer incidence rates in women who used HRT to those who did not that demonstrate the risks and benefits of HRT for chronic diseases," she said.
"Women need to discuss with their doctors the risk and benefits of taking HRT for the primary prevention of chronic disease, including breast cancer," she added.
Narod said hormone replacement is an excellent therapy for some women. Therapy that includes progesterone carries more risk, he said, and limiting use to five years or less seems wise.
Shapiro has performed consulting work for the manufacturers of hormone therapy, and Panay has received grants from pharmaceutical companies.