February 6, 2009 – The reduction in the number of breast cancer cases recently observed in the United States – as well as in Canada – is indeed attributable to the massive abandonment, since 2002, of hormone therapy by postmenopausal women .
According to American researchers, their results confirm the direct link between taking hormones that combine estrogen with progestins and the increased risk of developing breast cancer. The authors of the study1 compiled the records of more than 15,000 women who took part in the US Women Health Initiative (WHI) study.
The results show that postmenopausal women who took hormones for five years or more had a 28% higher risk of developing breast cancer than those who did not take hormones.
In fact, hormone therapy is responsible for six to eight additional cases of breast cancer, for every 10,000 women who take replacement hormones, according to the study.
However, the risk would be low in those who take hormones for less than two years. In addition, the risk of developing breast cancer would decrease quickly after stopping treatment.
Ironically, these results are made public just two weeks after the Society of Obstetricians and Gynecologists of Canada (SOGC) released new guidelines to reassure doctors and their patients about hormone therapy.
In particular, the SOGC recommends that doctors suggest hormone therapy for four to five years, or until the symptoms of menopause go away. The body even recommends starting hormone therapy at the onset of menopause. This position, however, is not unanimous among gynecologists.
Recall that in 2002, the WHI study was stopped after the results showed an increased risk of cancer in women who took a combination of estrogen and progestogen. After the publication of these results, women overwhelmingly stopped their treatment. A few years later, there was a marked decrease in the number of breast cancer cases in the United States and Canada.
The point of view of a menopause specialist
According to the study, this drop in the number of cases is attributable to the massive discontinuation of hormone therapy by postmenopausal women. What doubts the gynecologist Sylvie Dodin2. “Physiopathologically, it usually takes longer to be able to diagnose breast cancer than it took during the study,” she notes.
In Quebec, 20% of postmenopausal women would use hormone therapy, according to the menopause specialist. Before 2002, this proportion was 35%.
What should patients and doctors take away from the recent results of the WHI study?
“This is an important public health message that must be taken into account, but the choice of whether or not to take hormones must be based on the overall risk that a woman runs of developing breast cancer”, underlines the DD Dodin.
Also she believes that hormone therapy should be reserved for women who experience significant symptoms during their menopause, 20% to 25% of them.
“The important symptoms are those which disturb the quality of life to such an extent that a woman comes to stop all physical activity, to eat badly, to sleep badly and to no longer have energy”, specifies the gynecologist.
What about those with lesser symptoms? She recommends taking omega-3 capsules daily, eating a healthy diet and getting more physical activity.
Smaller doses of hormones?
In her practice as a gynecologist, Sylvie Dodin says that she generally prescribes the smallest possible doses of hormones to her patients. But for now, she does not know if small doses are associated with a lower risk of breast cancer.
“In real life, it is illusory to think that after five years of hormone therapy, we can stop treatment for women who experience severe symptoms during menopause,” she pleads.
This is why she believes that a study should be carried out to verify whether lower doses of estrogen – alone or in combination – reduce the risk of cancer “so that we can continue to help those who really need it” .
Martin LaSalle – PasseportSanté.net
1. Chlebowski RT, et al, Breast Cancer after Use of Estrogen plus Progestin in Postmenopausal Women, New England Journal of Medicine, February 5, 2009, Vol. 360, 573-587.
2. The DD Sylvie Dodin is an associate professor in the Department of Obstetrics and Gynecology at Laval University, and a clinical researcher at the Saint-François-d’Assise Hospital Research Center of the Center hospitalier universitaire de Québec. Gynecologist in the same establishment, DD Dodin is a consultant physician at the Center de santé publique and founding director of the Center Ménopause Québec.