Short pauses in hormone therapy don’t improve mammography

Older women who take a short break from hormone therapy do not experience fewer false positives on their screening mammograms than women who continue to take the drugs, though a suspension is associated with small changes in breast density.

Until now, it has been recommended that women suspend their hormone therapy for longer than three months under the assumption the pause will help reduce false positives responsible for unnecessary recalls and diagnostic mammography.

But a study at the Group Health Center for Health Studies in Seattle, WA, found that recall rates were 11.3% among the women who did not suspend hormone therapy, 12.3% for those who suspended therapy for one month, and 9.8% for those who suspended therapy for two months (Ann Intern Med 2009;150:752-765). The differences were not statistically significant.

 

Although halting therapy did not significantly affect recall rates, breast density–a characteristic associated with higher recall rates–slightly decreased.

The study covered 1704 menopausal or post-menopausal women aged 45 to 80 on hormonal therapy. Volunteers were randomly assigned to receive screening mammography without ceasing hormone therapy, ceasing therapy one month before mammography, or ceasing therapy for the two months before mammography.

Women who suspended hormone therapy for one month experienced a 0.9% decrease in breast density. Women who suspended therapy for two months saw a 1.5% decrease while women who stayed on hormone therapy experienced no change.

Menopausal symptoms increased when therapy was suspended and many women were adamant about sticking with the drugs when they were contracted about participating in the trial. Two-thirds of 5861 potential volunteers were ruled out because they refused to suspend hormone therapy.

The resistance to dropping hormone therapy suggests women are either not likely to comply with the protocol, or wouldn't participate in the study even if it meant reducing false positive rates, said Diana S.M. Buist, principal investigator.

The study proves, however, there is no benefit from stopping hormones for one to two months before a mammogram to try to improve mammographic quality, she said. Women who stop hormones for longer than two months however, are likely to see improvements in mammography based on results from other trials.