Taking hormone drugs for more than ten years could help to dramatically reduce the risk of breast cancer recurrence, according to a landmark study.

A randomised clinical trial involving nearly 2,000 women found that cancer recurrence dropped by a third in those who took hormone drugs for ten years rather than the standard five.

Hormone therapy is given to the women with ER-positive breast cancer in order to stop the body from producing oestrogen, which helps to drive the growth of tumours in this type of breast cancer.

The study, which was presented to the American Society of Clinical Oncology (ASCO), involved women who had already received hormone therapy for at least five years.  

All had taken an aromatase inhibitor for at least five years before enrolling in the trial and some had taken tamoxifen prior to this.

The trial randomly split the women into two groups – one group received a further five years of the aromatase inhibitor letrozole, while the other group received a placebo. 

The study found:

  • Women in the extended letrozole group had a 34 per cent lower risk of breast cancer recurrence.
  • At five years of follow-up, 95 per cent of women receiving letrozole and 91 per cent of those receiving placebo were breast cancer free.
  • There were no significant differences in either overall quality of life or menopause-specific quality of life between women who took letrozole for five years and those who received placebo.

ASCO breast cancer expert, Dr Harold Burstein, says the results are significant.

“These data are important to the millions of women around the world with ER positive breast cancer, and suggest that longer durations of widely-available therapy reduce the risk of cancer recurrence, and prevent second cancers from arising,” he says.

“Ten years of any therapy is a long time. Fortunately, most women tolerate extended treatment reasonably well, with few side effects. Now, women can talk with their clinical team and make informed decisions to extend adjuvant endocrine therapy, or not.”

BCAC chairperson, Libby Burgess, says the evidence is now overwhelming that taking hormone therapy for a longer duration offers protection against breast cancer recurrence.

“BCAC strongly advises women to speak with their medical team about how long they should take hormone therapy for in light of this research. 

“We also urge women to speak up about any side-effects they encounter taking this type of medication so that those can be appropriately managed in order to help women to take hormone therapy for longer,” she says. 

Read more here.

27 June 2016

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