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ATLAS Tamoxifen Study

 A new study shows that the tried and true breast cancer drug tamoxifen is more effective when used for 10 years instead of the currently recommended five years of therapy.

A study on the breast cancer drug tamoxifen that was recently released at the San Antonio Breast Cancer Symposium and published in the medical journal The Lancet, has been log awaited as it represents one of the  argest breast cancer trials of its type. The study called "The Adjuvant Tamoxifen: Longer Against Shorter", or simply ATLAS, is a large multi-center study that began in 1996 and looked at over 12,000 women with early stage breast cancer. The ATLAS study is important because it could change the way oncologists practice their trade. The results contain the research team's conclusion that extending the use of tamoxifen up to 10 years instead of the currently recommended five years of therapy might be able to save a significant number of lives because the 10-year therapy regimen was found to be far more effective at halting the return of breast cancer.

Anything that can lower the risk of breast cancer coming back is welcomed by physicians today because so many cases of breast cancer that appear to be "cured" eventually recur even after years of treatment. The study looked at tamoxifen specifically because it has traditionally thought to be been the most effective hormone therapy drug available to treat the three quarters of all breast cancers that are estrogen receptor positive. The new 10-year study differed from prior research that failed to show a clear benefit of taking tamoxifen for longer than five years because the past studies simply stopped looking at the data after the 5-year mark had been reached, and the new trial shows that lives could be saved by taking tamoxifen for longer periods of time. The study's lead author Dr. Christina Davies said in a statement that "Five years of adjuvant tamoxifen is already an excellent treatment that substantially reduces the 15-year risk for recurrence and death. We now know that 10 years of tamoxifen is even better, approximately halving breast cancer mortality during the second decade after diagnosis."

That the reoccurring breast cancers and deaths were lower for women who took tamoxifen for 10 years instead of just five years showed up when comparing the women who died of breast cancer during the follow-up period of the study to those women who continued tamoxifen longer. The results showed that there was a definite improvement in the mortality rates during the 10 years of the trial. The results also pointed out that while tamoxifen has been used successfully for over a decade, there is a risk that taking more of it for longer periods of time could have negative consequences in the form of higher risks of developing uterine cancer and blood clots. This fact was partially addressed when Dr. Harold Burstein of the Harvard Medical School told the Symposium guests that "The data may push more patients to consider longer durations of anti-estrogen therapy. Patients will also need to be aware of the trade-offs, including mild side effects and more serious but rare cancer risks."

Thsee new tamoxifen findings show a need for longer follow-up after breast cancer trial studies, but overall, the benefits appear to outweigh the risks. Dr. Len Lichtenfeld of the American Cancer Society summed up the conclusion when he said "Many would like to think that five or 10 years out they are safe. But unfortunately there are women who will have a relapse and die from breast cancer, and that's why this study is of importance, because this may warrant longer treatment and it shows that in breast cancer, long term trials are important."

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