Breast cancer survivors who are having trouble with menopausal symptoms should find a treatment other than hormone replacement therapy (HRT), according to a new study. Researchers from Sweden found that hormone treatment significantly raised the risk of a recurrence in women who had been previously treated for breast cancer. They stopped their study ahead of schedule because the risk was "unacceptably high."

The finding, published in the online version of The Lancet, is just the latest blow to hormone therapy, which has been on the decline since several major studies linked it to breast cancer, heart disease, and other serious conditions.

But hormone therapy is one of the few effective treatments available to help women cope with the sometimes debilitating night sweats, hot flashes and other problems associated with menopause. Many healthy women still use it, despite the new findings about its risks. And some previous studies seemed to indicate that short-term use would be safe, even for breast cancer survivors. The Swedish study was designed to test that theory.

The researchers randomly assigned 174 survivors to receive hormone therapy (either an estrogen-progesterone combination or estrogen-only if they'd had a hysterectomy), while another 171 survivors were given other treatments for menopause symptoms. Hormone therapy was given for only 2 years.

Twenty-six women in the hormone therapy group developed a second breast cancer, and most of those recurred during hormone treatment. Just 7 women who received alternative treatments had a recurrence. Also, more women in the hormone group experienced serious side effects from their treatment.

The differences were so dramatic that the researchers stopped the trial and advised all the study participants on hormone therapy to stop taking the medication.

The findings complicate the treatment of menopause symptoms in breast cancer survivors, said Rowan T. Chlebowski, MD, PhD, a medical oncologist at Harbor-UCLA Research and Education Institute in Torrance, California. Chlebowski has studied hormone therapy extensively and wrote an editorial accompanying the Swedish study.

"Breast cancer survivors are left with a very big problem now," he said.

The results of this new study, combined with findings from the Women's Health Initiative and the Million Women Study, suggest that hormone therapy is just too dangerous for this group of women, he said. Even women who don't have a history of breast cancer might want to take the newest study into account when deciding whether to try hormone therapy, he said.

"I think it's going to influence some women to really consider carefully whether to take menopausal hormones," said Chlebowski. "It's not directly applicable, but it gives them something to think about."

Unfortunately, alternative treatments for menopause symptoms are few.

Antidepressants known as selective serotonin reuptake inhibitors (SSRIs) have been used with some success, he noted. Getting more exercise may also be helpful, though there isn't much data about how effective that might be, Chlebowski noted.

What's really needed are new drugs to help women manage menopause symptoms, he said.

The need is especially urgent, he said, because the Swedish study, though not necessarily definitive, is likely to be the "last word" on hormone therapy for breast cancer survivors. Other experts agreed.

"In the past, some doctors have offered HRT to selected breast cancer survivors because a handful of small, preliminary studies had failed to show a risk," said Harmon J. Eyre, MD, chief medical officer of the American Cancer Society. "This study will no doubt change that. It is large enough and clear enough to show that… offering HRT to women with a history of breast cancer would be unwise."