Breast cancer

06 June 2016

Longer hormone therapy reduces breast cancer recurrence

Data suggest that extended use of widely available therapy reduces the risk of cancer recurrence, and may prevent second cancers from occurring.

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Doubling the duration of hormone therapy for women with early-stage breast cancer from five to 10 years reduces the risk of recurrence and developing tumours in the other breast, a study shows.

Lower risk of recurrence

The study focused on a type of early-stage breast cancer known as hormone receptor-positive and was presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago this weekend. It also appears in the New England Journal of Medicine.

Postmenopausal women who took the drug letrozole for a decade instead of an often prescribed five-year period saw a 34 percent lower risk of recurrence or of a new cancer in the other breast than those who received a placebo, according to researchers.

Letrozole is an aromatase inhibitor, which stops oestrogen production in postmenopausal women.

Read: Less intrusive breast cancer treatment can save many lives

Data suggest that "longer durations of widely-available therapy reduce the risk of cancer recurrence, and prevent second cancers from arising", said Harold Burstein, a breast cancer expert and associate professor of medicine at Harvard Medical School not linked to the study.

Lead study author Paul Goss, director of breast cancer research at Boston's Massachusetts General Hospital, said women with early stage hormone-receptor positive breast cancer face an "indefinite risk of relapse".

Promising statistics

The study involved 1,918 postmenopausal women in Canada and the United States who had received five years of any one of three aromatase inhibitor therapies either as initial treatment or after taking tamoxifen, another anti-oestrogen drug dating back to the 1970s.

Read: Less radiation better for early breast cancer

Half of the participants received letrozole after a random selection process, while the other half received a placebo.

After a follow-up period of a little more than six years, just seven percent of participants in the letrozole group saw a recurrence of cancer or a tumour in the other breast, compared to 10.2 percent in the control group.

But only 1.4 percent of the women on letrozole developed a cancer in the breast that had been spared, compared to 3.2 percent of those on the placebo.

As concerns recurrence of the initial cancer most frequently in the bones, liver or other organs the difference between the two groups was smaller 5.7 percent in the letrozole group versus 7.1 percent in the control group.

Read: Breast cancer: the latest research

At five years of follow-up, 95 percent of the women receiving letrozole were free of breast cancer, compared to 91 percent in the control group.

Ninety-four percent of the women taking letrozole had survived at the five-year mark, compared to 93 percent of those taking a placebo.

In 2012, more than six million women around the world survived for at least five years after being diagnosed with breast cancer according to statistics cited by ASCO.

Read more:

Symptoms of breast cancer

Treating breast cancer

Preventing breast cancer

 

Ask the Expert

Breast cancer expert

Dr Gudgeon qualified in Birmingham, England, in 1968. She has more than 40 years experience in oncology, and in 1994 she founded her practice, Cape Breast Care, where she treats benign and malignant breast cancers. Dr Boeddinghaus obtained her qualification at UCT Medical School in 1994 and her MRCP in London in 1998. She has worked extensively in the field of oncology and has a special interest in the hormonal management of breast cancer. She now works with Dr Gudgeon at Cape Breast Care. Read more.

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