The Canadian Cancer Society is urging women to avoid combination hormone replacement therapy, saying the drug poses a real increase in the incidence of breast cancer among long-term users.
The warning is meant to clarify confusing messages about the risks and benefits of the therapy, which has come under intense scrutiny since a massive U.S. study found the drugs can actually increase the risk of stroke, heart attack and breast cancer.
“The strength of the evidence now is very compelling and the (Women’s Health Initiative) trial is a very strong, very carefully thought-out study. Women need to know the risks and benefits so they can carefully consider them,” said Heather Logan, director of cancer control policy for the Canadian Cancer Society.
Although the results of the WHI trial were released in the summer of 2002 when the study was suddenly halted as researchers realized the seriousness of their findings Logan said the society waited to issue a policy directive until they had thoroughly sorted through all the studies surrounding HRT.
“We’ve been following those journals and publications very carefully and have been reviewing them on an on-going basis and they’re really strengthening the initial message that the risks outweigh the benefits,” she said.
A recent U.S. study published in the Journal of the American Medical Association found that the number of women using combination hormone therapy had plummeted by half since the WHI findings were announced in 2002.
Some doctors said this kind of statement from the Canadian Cancer Society keeps women who need drug therapy from seeking treatment.
“I have so many patients who really should be on hormones who are terrified to take it now because of all this media stuff,” said Dr. Sandy Messner, medical co-ordinator of breast cancer prevention services at Sunnybrook and Women’s College Health Sciences Centre.
However, Logan said the warning shouldn’t be seen as black and white, but should lead to a discussion between a woman and her doctor about what’s really right for her based on the medical evidence.
“We hope that (the policy initiative) carries the right amount of weight so that women make the right decision, so that they’re informed,” Logan said.
The WHI study followed 16,000 post-menopausal women taking hormone replacement therapy.
It found that a woman’s risk of breast cancer increases after using combination HRT for more than four years. There was no significant increase of breast cancer risk for women taking HRT less than four years.
A clinical trial involving estrogen-only therapy is still ongoing and expected to report in 2005.