HRT study halted due to breast cancer risk

 A Swedish study assessing the effect of hormone replacement therapy (HRT) on women with a history of breast cancer has been stopped prematurely after preliminary results showed an "unacceptably high" level of breast cancer in HRT users. The steering committee of the study, published in The Lancet, was called to a halt after 26 women out of 345 survivors in the project reported a recurrence (or new case) of breast cancer.

Lead investigator, Lars Holmberg, explained: "The 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".

Mr Holmberg said that the women would receive ongoing support and that the steering committee would continue to collaborate with other ongoing studies in the field.

"Alternative safe and effective strategies for the difficult problem of menopausal symptoms in these women now need to be developed," the researchers concluded.

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 The Lancet 

Press Release: Monday, 2nd February (Lancet)

 HRT TRIAL STOPPED EARLY AFTER 'UNACCEPTABLE RISKS'
FOR WOMEN WITH PREVIOUS BREAST CANCER

A Swedish study established to assess the effect of hormone replacement
therapy (HRT) for women with a history of breast cancer has been stopped
early after preliminary results show 'unacceptably high' risks of breast
cancer recurrence for HRT users. The results are published online by THE
LANCET (3 February 2004) and will appear in the February 7 print edition.

The increasing survival of women with breast cancer has made the management
of menopause (either natural or early-onset due to hormone therapy or
chemotherapy) an important clinical issue. The HABITS trial (Hormonal
replacement therapy after breast cancer diagnosis-is it safe?) was one of
several trials established in the 1990s to assess the possible risk of
recurrent breast cancer for women using HRT. Originally planned to include
at least 1300 women followed up for five years, the trial was stopped on
December 17, 2003, after an average follow-up of just over two years. The
steering committee for the trial were concerned that early results from the
study showed an unacceptably high risk of recurrent breast cancer for those
women randomised to receive HRT; of 345 women (all of whom had had previous
breast cancer and were randomised to HRT or no HRT) with at least one
follow-up assessment, 26 in the study arm allocated HRT reported a
recurrence (or a new case) of breast cancer, compared with seven women who
received therapy other than HRT for menopausal symptoms.

Lead investigator Lars Holmberg from University Hospital Uppsala, Sweden,
comments: '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. However, the women in the
trial will be followed up for many years and the steering committee of the
HABITS trial will continue to collaborate with other ongoing studies in the
same clinical domain.'

In an accompanying Commentary, Rowan T Chlebowski (Harbor-UCLA Research and
Education Institute, USA) and Nananda Col (Brigham and Women's Health
Hospital, Boston, USA) conclude: '...considering all available evidence
about the effect of hormone therapy on breast cancer and chronic disease,
the HABITS investigators' conclusion that even short-term use of hormone
therapy poses an unacceptably high risk of breast cancer can now reasonably
guide clinical practice for women with breast cancer...Alternative safe and
effective strategies for the difficult problem of menopausal symptoms in
these women now need to be developed'.

  

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