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Widely Available Hormone Drug Cuts Breast Cancer Recurrence By A Third If Taken For Ten Years

Breast cancer mammogram
The drug is already widely taken by women following breast cancer treatment. Gushenkova/Shutterstock

The results of a recent study have been announced at the world’s largest cancer conference, getting top billing due to the astonishing results. By doubling the amount of time that women were given a specific drug that blocks estrogen production – from five to 10 years – the researchers were able to cut the rate at which patients experience cancer recurrence by 34 percent. But as some of the women in the trial had already been on the drug before it started, some of the women will have been taking the drug for 15 years.

The drug, known as an aromatase inhibitor, works by blocking the body’s production of estrogen. It is already known that roughly four-fifths of all breast cancers are caused by the female hormone, and the risk of them developing subsequent cancer can last for years after the initial tumor has been removed. Some drugs, such as tamoxifen, act by preventing the estrogen from entering the breast cells, while aromatase inhibitors take a bit more of a blanket approach.


The trial, the results of which have been published in the New England Journal of Medicine, involved 1,918 women who had been diagnosed with breast cancer but had the tumor removed. They found that in those women who were prescribed the extra medicine, which meant giving it to them for 10 years rather than five, 95 percent of them were cancer free at the end of the trial. For those women who were given the drug for the standard five years, only 91 percent were still tumor free.

With a huge number of women already taking hormonal drugs post diagnosis, these findings could be massive. “[The study] will have an enormous impact, a reduction in recurrences is a very important finding,” explained Professor Paul Goss, one of the researchers, to the BBC. “Aromatase inhibitors are now readily available around the world and therefore our results will further improve the outcome of women with breast cancer globally.”

There are, as always, some side effects. As a result of the new treatment, and taking the drug for such an extended period of time, it does increase the risk of osteoporosis and bone fractures. Blocking the production of estrogen also has other impacts, such as the loss of libido, hot flushes, as well as vaginal dryness. This, the researchers say, means that any decision to continue taking the drug should be made between the doctor and the patient, looking at what is best on an individual basis. While the new treatment may not be applicable for every woman recovering from breast cancer, with 1.7 million diagnoses globally a year, it could still have a dramatic impact on the number who develop it for a second time. 


healthHealth and Medicine
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  • cancer,

  • breast cancer,

  • tumor,

  • hormone,

  • estrogen,

  • remission