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Tuesday, 2 January, 2001, 23:47 GMT
Tamoxifen heart disease link ruled out
The drug prevents breast cancer developing
The drug prevents breast cancer developing
The breast cancer prevention drug tamoxifen does not increase the risk of developing heart disease, researchers have found.

A team in Pittsburgh, USA, has carried out the largest study into the cardiovascular risk of tamoxifen.

Experts had been concerned tamoxifen could affect women's heart disease risk as it can bring forward the menopause, after which women become more prone to developing heart problems.

Over 13,000 women at increased risk of developing breast cancer were monitored between 1992 and 1997. Some had already suffered from heart problems.

Researchers compared the risk of women who were taking tamoxifen and women who had been taking a placebo, and found no statistical difference.

These findings should provide a degree of comfort to those women who are taking tamoxifen for breast cancer prevention

Prof Steven Reis

'No difference'

Professor Steven Reis, who led the research team, said: "We found that cardiovascular event rates were not statistically different between women randomly-assigned to tamoxifen or placebo, independent of pre-existing coronary heart disease."

"These findings should provide a degree of comfort to those women who are taking tamoxifen for breast cancer prevention."

The study, published in the Journal of the National Cancer Institute, is part of the national US breast cancer prevention trial.

After initial checks in 1992, the scientists carried out follow-up checks on 13,194 women.

Of the group, 1,048 had experienced coronary heart disease, such as heart attacks or angina, before the study began, and 12,146 had not.

Half the 13,000 were taking tamoxifen, the rest the placebo.

More research needed

Women who had previously had a heart problem did have a higher rate of cardiovascular events.

But there was virtually no difference in the proportion of the group taking tamoxifen and the group taking the placebo who suffered any kind of heart problem.

And there was no difference at all when the scientists looked at fatal and non-fatal heart attacks, and unstable or severe angina.

Professor Reis added: "Although the event rates in the group of women with a prior history of heart disease are greater than those observed in the group of women without a history of heart disease, these data demonstrate that assignment to tamoxifen did not affect cardiovascular events in this high-risk population.

"Because tamoxifen is increasingly being prescribed for the prevention and treatment of breast cancer, longer-term clinical trials of tamoxifen in women are needed to further elucidate its long-term cardiovascular effects."


Kate Law, head of clinical trials at the Cancer Research Campaign said there had been some concern over the effects of tamoxifen on coronary heart disease risk, because the drug can cause premature menopause, and women have a greater risk of heart disease following the menopause.

"This is a very reassuring study, The importance is that when you've got breast cancer and you've got an effective drug, you trade off the risks and benefits.

"When you give it as a preventative drug, you're giving it to healthy women and you worry it might be causing more deaths."

A UK study is following 7,000 women taking tamoxifen as a preventative drug.

The study, which started seven years ago, will monitor breast cancer deaths and deaths from other causes.

Dr Christina Davies, tamoxifen trial co-ordinator for the Imperial Cancer Research Fund, said more extensive research was needed.

"They haven't really got enough to draw adequate conclusions. What they have said is reasonable but, as they themselves say, we need to have longer clinical trials and more data."

A British Heart Foundation spokeswomen said: "This research could reassure women that using tamoxifen does not increase their risk from cardiovascular diseases.

"Earlier studies have actually shown that tamoxifen can help to reduce certain risk factors for coronary heart disease."

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19 May 00 | Medical notes
01 Oct 99 | Health
Tamoxifen works in smaller doses
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