HRT trial halted amid breast cancer fears

Doctors have halted another major HRT study after early findings showed women were being made to face an “unacceptably high risk” of breast cancer, it was revealed today.

The Swedish trial was set up to assess the effect of hormone replacement therapy on women with a previous history of the disease.

It was stopped three years early when the results showed that HRT significantly increased the chances of recurring breast cancer or the appearance of a new tumour.

The study, known as Habits (hormonal replacement therapy after breast cancer diagnosis – is it safe?), was originally meant to include at least 1,300 women monitored for five years.

Doctors halted it on December 17 last year after an average follow-up of just two years.

Of 174 women assigned to hormone replacement therapy, 26 reported a recurrence or new case of breast cancer.

In contrast, only seven women who received therapy other than HRT for menopausal symptoms re-encountered the disease.

All the women taking part in the trial had been successfully treated for breast cancer in the past.

Most were given HRT consisting of a combination of oestrogen and progestagen hormones.

Women whose wombs had been removed were recommended a medium-strength oestrogen-only treatment.

Chief investigator Lars Holmberg, from University Hospital, Uppsala, Sweden, said: “The Habits trial was terminated because women with a history of breast cancer allocated to receive HRT for menopausal symptoms experienced an unacceptably high risk of breast cancer,compared with breast cancer survivors allocated to best symptomatic treatment without hormones.

“Women on active treatment have been advised to discontinue.”

Serious concerns about the safety of HRT were raised in 2002 when a large American trial was abandoned.

The Women’s Health Initiative study involved more than 16,000 women and was the biggest HRT safety investigation ever undertaken.

It was stopped after five years – three years early – because the risks so clearly outweighed the benefits.

Taking a combined HRT pill increased the risk of breast cancer by 26%, of a heart attack by 29% and of a stroke by 41%, the findings showed.

The Department of Health pointed out that the type of HRT used in the study was not available in the UK, and women were urged not to panic.

Later the same year, the Medical Research Council halted a British HRT trial started in 1999 which was intended to last 13 years.

The MRC said the decision was taken for practical reasons and not on safety grounds. Continuing the UK trial seemed pointless and time-consuming since the American study had covered similar territory.

The Swedish findings appeared today in an early online publication by The Lancet medical journal.

It was accompanied by a commentary from two US experts.

Rowan Chlebowski, from the Harbor-UCLA Research and Education Institute in Torrance, California, and Nananda Col, from Brigham and Women’s Health Hospital in Boston, Massachusetts, said: “Although the Habits investigators did not report on menopausal symptoms or quality of life, their finding that hormone therapy increases recurrence risk complicates the management of menopausal symptoms in women with breast cancer.

“Alternative safe and effective strategies for the difficult problem of menopausal symptoms in these women now need to be developed.”