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AUTHORS: Lars Holmberg
ABSTRACT: Swedish researchers stopped a study examining the impact of hormone replacement therapy (HRT) in women with a history of breast cancer because of an unacceptably high risk of recurrence of the disease.
COMMENTARY: The study, originally planned for five years, was halted after only two because more than three times as many women taking HRT had a recurrence or new breast tumor compared to women who received other treatments to relieve symptoms of the menopause.
"We thought we found an unacceptably high risk for a new breast cancer event in women taking HRT," said lead investigator Lars Holmberg, of the University of Uppsala in Sweden.
"Patient safety must be first. We felt the risk was too high," he added.
After two years of follow-up, 26 women in the group allocated to receive HRT had a recurrence or new cancer, compared to seven in the other group not on hormone treatment.
More than 345 women who had had breast cancer took part in the study. They were randomized to receive either HRT or a non- hormonal treatments.
"Women on active treatment have been advised to discontinue," said Holmberg, whose findings were published online by The Lancet.
Millions of women have used HRT to relieve hot flushes, mood swings and sexual problems linked to the menopause and to stave off osteoporosis, or brittle bone disease.
The Swedish decision followed moves by American and British scientists who also stopped HRT trials after learning HRT may increase the risk of breast cancer, stroke and blood clots.
An analysis of four major studies into the effects of HRT by scientists at the British charity Cancer Research UK supported the U.S. findings.
The review showed that women who took the treatment for five years had a higher risk of breast cancer, stroke and blood clots in the lung but were less likely to suffer from bowel cancer or hip fractures.