Can Breast Cancer Survivors Take Hormones?
Study Suggests Some Forms of Hormone Therapy May Be Safe
April 5, 2005 -- New research suggests that some forms of menopausal hormone therapy may be safe for use by breast cancer survivors, but experts say too many safety questions remain to recommend that these women take hormones to relieve menopausal symptoms.
The Scandinavian study found no association between the use of menopausal hormone therapy and breast cancer recurrence in early-stage breast cancer survivors who took hormones for an average of four years.
The findings stand in sharp contrast to those of another major Swedish study on hormone therapy in breast cancer survivors published in December 2003. Researchers reported a threefold increase in cancer recurrences among survivors treated with hormones compared with survivors who did not take hormone therapy.
The seemingly contradictory results mean that it is still too soon to recommend hormone therapy for women with a history of breast cancer, an author of the newest research tells WebMD.
"Breast cancer survivors should not take hormone therapy because we still know way too little about its effect [on cancer recurrence]," says Eva von Schoultz, PhD.
"The hope is that our new findings will stimulate discussion and research about whether certain types of hormone therapy are safe for this group of women."
Hormone therapy with estrogen alone in women who have had hysterectomies -- or estrogen plus progestin in those who haven't -- is considered to be the best treatment for hot flashes and other symptoms of menopause.
Its long-term use was linked to an increased risk of breast cancer, heart disease, and stroke in a widely publicized 2002 Women's Health Initiative (WHI) study. But limited use and low dosages specifically for the relief of menopausal symptoms is now generally considered to be safe for women with low cardiovascular and breast cancer risk.
The original intent of the two Swedish studies, begun prior to the publication of the WHI findings, was to assess the safety of long-term hormone therapy treatment in breast cancer survivors. The "Hormonal Therapy After Breast Cancer -- Is It Safe?" trial was stopped early after researchers reported the threefold increase in cancer recurrences among former patients who had taken hormones for just two years.
The newly reported Swedish trial is published in the April 6 issue of the Journal of the National Cancer Institute.
Although the two trials were similar, more women in the newly reported study got hormone therapy with estrogen alone. Also, those who took combination therapy with a progestin got a different schedule of dosing than routinely given to menopausal women. Instead of the hormones being given continuously and combined, as is routinely done in the U.S., progestin was given for just 14 days over three months.
The authors suggest that the differences in dosage and timing could explain why they found no increase in breast cancer recurrences in their treatment group. But they added that more study is needed to prove this.