New study suggests Tamoxifen treatment should be extended to 10 years

Those individuals who buy Tamoxifen to treat and prevent the onset of breast cancer following primary treatment know that it is widely considered to be a blockbuster drug that offers protection against recurrence of the disease.

ER-positive breast cancer treatment
Usually prescribed over the course of five years, Tamoxifen can be bought from an online pharmacy and is considered a type of treatment for women with estrogen receptor (ER)-positive breast cancer, as it blocks the effects of the hormone, notes the Mayo Clinic. For this population, however, adjuvant therapy - or treatment following primary care - involving Tamoxifen is even more effective over a period of 10 years, according to a recent study.

Research on the appropriation of Tamoxifen over a decade was conducted by Christina Davies, M.D., a coordinator in the Clinical Trial Service Unit at the University of Oxford, and funded by various cancer research institutions. Published in the Lancet journal, the international study, titled Adjuvant Tamoxifen - Longer Against Shorter (ATLAS), was also presented at the 2012 San Antonio Breast Cancer Symposium.

"ATLAS showed that protection against breast cancer recurrence and death is greater with 10 years than with five years of Tamoxifen use," explained Davies. "Women and their doctors should be aware of this evidence when deciding how long to continue Tamoxifen, or any other endocrine treatment."

How Tamoxifen works
A common hormonal or endocrine therapy, Tamoxifen binds to tissues that use estrogen, limiting the ability for breast cancer cells to grow, notes the National Cancer Institute. According to the agency, studies have shown that Tamoxifen can prevent the growth of the original cancer cell and limits the development of new cancer in premenopausal and postmenopausal women.

Davies and the team of researchers surveyed 6,846 women with ER-positive breast cancer from the years 1996 to 2005. All the participants had been using Tamoxifen for the standard five years. Over the course of the study, participants were randomly assigned to either stop their medication after five years or to continue taking the drug.

After the follow up, the researchers noted that, compared to the participants who stopped, those women who continued treatment had their recurrence rates lowered by 25 percent, while mortality rates were reduced by 29 percent.

"We already knew that five years of Tamoxifen reduces breast cancer mortality in this late period by almost a third in comparison with no Tamoxifen," said Davies. "We now know that 10 years of Tamoxifen is even better, approximately halving breast cancer mortality during the second decade after diagnosis."