Hormone drugs can increase cancer risk
HORMONE replacement therapy can triple the risk of breast cancer, the biggest ever study into the drug has found.
Following more than a decade of controversy, researchers believe that the risks have been underestimated and the longer women take one of the most commonly prescribed pills, the higher their chances of getting the disease.
The National Institute of Health and Care Excellence (Nice), which last year changed its guidance to encourage more doctors to prescribe HRT, claiming that too many menopausal women had been left suffering in silence, said its advice remained that the benefits may outweigh the risks.
HRT is used to treat uncomfortable symptoms of the menopause, such as hot flushes, migraines, disrupted sleep, mood changes and depression, by topping up the decreased levels of hormones produced by the body.
But doctors were reluctant to prescribe it after a study in 2002 suggested it could raise the risk of cancer, a claim later widely disputed.
Now new findings by the UK Institute of Cancer Research and Breast Cancer Now suggest the original risk had actually been underestimated.
The study of 100 000 women over 40 years found that those who took the combined oestrogen and progestogen pill for around five years were 2.7 times more likely to develop cancer compared with women who took nothing, or only the oestrogen pill.
The risk rose to 3.3 times for women who took the drugs for 15 years or more.
Around 14 in 1 000 women in their 50s are expected to develop breast cancer, but that rises to 34 in 1 000 for women taking the combined pill, the study suggests.
“Our research shows some previous studies are likely to have underestimated the risk of breast cancer with combined oestrogen-progestogen HRT,” said the study leader, Institute of Cancer Research, London epidemiology professor Anthony Swerdlow.
“We found that current use of combined HRT increases the risk of breast cancer by up to threefold, depending on how long HRT has been used. Our findings provide further information to allow women to make informed decisions about the potential risks and benefits of HRT use.”
HRT was first developed in the 1940s and was first made available to women in Britain in 1965. However, in 2002 the British Millennium Women Study published findings claiming that HRT raised the risk of cancer. Many doctors immediately withdrew prescriptions while the Medical Healthcare and Regulatory Agency (MHRA) issued new guidance recommending that the “lowest effective dose should be used for the shortest time”.
Since then the number of women taking HRT has more than halved with around one in 10 eligible patients now using the drugs, approximately 150 000 women. Around 40% take the combined pill. More recently, a review by Imperial College and a 10-year study by New York University found no evidence of a link, adding further to the confusion.
Last year, Nice changed its guidance to encourage doctors to offer HRT, claiming one million women were being forced to “grit their teeth” and live with menopausal symptoms.
At the time, the health watchdog said the cancer risk was 27 in 1 000, so the new research increases that risk by 25%.
However, the health watchdog said the new study should not change how doctors prescribe HRT.
Prof Mark Baker, director of the Centre for Guidelines at Nice, said: “As with Nice guidance, this study recognises there is no increased risk of breast cancer with oestrogenonly HRT but the combined HRT can be associated with an increased risk of breast cancer.
“The guideline makes clear that menopausal women should be informed that the impact of HRT on the risk of breast cancer varies with the type of HRT used.”
Prof Baker added: “The message from our guidance to women is clear – talk about the menopause with your clinician if you need advice on your symptoms – it’s very important to discuss the options to find what might help you.”
The new study also found that the risk declined when women stopped taking HRT, and there was no danger at all for women only taking oestrogen, which accounts for half of all prescriptions.
Baroness Delyth Morgan, chief executive at UK’s Breast Cancer Now, said: “Whether to use HRT is an entirely personal choice, which is why it’s so important that women fully understand the risks and benefits and discuss them with their GP.”
The research was published in the British Journal of Cancer. — The Daily Telegraph