Major HRT study halted over breast cancer fears

DOCTORS have halted another major hormone replacement therapy (HRT) study after early findings showed women were facing an “unacceptably high risk” of breast cancer, it was revealed yesterday.

The Swedish trial was to assess the effect of HRT on women with a previous history of the disease.

It was stopped three years early when results showed 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 to include at least 1,300 women monitored for five years.

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

Of 174 women assigned to HRT, 26 reported a recurrence or new case of breast cancer. In contrast, only seven women on therapy other than HRT for menopausal symptoms re-encountered the disease.

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 ... treatment without hormones.

"Women on active treatment have been advised to discontinue."

The findings appeared yesterday in an early online publication by The Lancet.

The picture is not clear, however, because another Swedish study has shown no increased risk of recurrent breast cancer from HRT.

The two trials, HABITS and the "Stockholm" study, were being run in tandem.

Consultant gynaecologist Malcolm Whitehead, director of the Amarant Trust, which advises women on HRT, criticised The Lancet for publishing too soon.

"We need to have the Stockholm data as well as the HABITS data, and we need to look for important differences in study design that might explain the results.

"I think these results have been published prematurely," said Mr Whitehead.