HRT safety trial abandoned after US health scare

British research into the long-term safety of hormone replacement therapy was halted yesterday – four months after a similar study in America was abandoned because the risks of HRT to women significantly outweighed the benefits.

The £20m UK study was scrapped after independent scientists said it was unlikely to add to lessons learned in America, where prolonged use of HRT was found to increase the risk of breast cancer, heart attacks, strokes and blood clots.

More than 5,700 women had been recruited to the 17-year trial, which was supposed to investigate the experiences of 16,000 post-menopausal women, aged from 50 to 69, until 2016.

But the Medical Research Council (MRC) scrapped the study after a panel of 12 international advisers said it was "unlikely to provide substantial evidence to influence clinical practice in the next 10 years".

One of the main reasons for starting the trial in 1999 was to test a theory that HRT would have a significant effect in protecting women against heart disease.

But the US results showed that HRT was riskier than had been previously thought and that women who used combined HRT for five years ran a 29 per cent increased risk of heart disease. They also ran a 26 per higher risk of breast cancer, although the drugs reduced their risk of bowel cancer and hip fractures.

Along with this new evidence, the UK study had been hindered by difficulties in recruiting women volunteers who were prepared to take HRT, or be studied as controls, over a period of up to 10 years.

Professor Ray Fitzpatrick, director of the University of Oxford's Institute of Health Sciences and chairman of the independent panel, said: "In 1999, there were important questions about the risks and benefits of taking HRT long term that needed to be answered. But since then new findings have provided evidence in relation to those questions.

"There is strong evidence that taking HRT long-term increases the risks of some diseases, such as breast cancer, and decreases the risks of others, such as osteoporosis. However, there is no trial evidence that HRT protects women from cardiovascular disease and it may even increase their risk in the short term."

The halting of the trial amounts to a U-turn on the MRC's position in July, when two separate committees said the work should continue, despite the US results.

Professor Fitzpatrick conceded that the original decision had been a mistake and that it would have been better if the announcement had not been made. A statement from his panel accepted that the trial, called Wisdom, could have provided more precise details of the health risks and benefits of HRT.

But it added: "There would be such substantial delays whilst Wisdom accumulated its target number of patient years that Wisdom would be unlikely to to make major contributions to clinical practice in the next 10 years."

The scientists stressed that their recommendation to stop the trial should not be read as a message for women to stop taking HRT altogether, because the health risks that had been identified related to long-term use.

In Britain, most women take HRT on a short-term basis to relieve mood swings and hot flushes. Patients who had concerns should consult their doctor before making any decision to change their medication, the scientists said.