ATLAS - Adjuvant Tamoxifen Longer Against Shorter

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Final recruitment: 15,252 women


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ATLAS is an international randomised clinical trial designed to determine reliably the optimal duration of adjuvant tamoxifen in early breast cancer (see page 2 of the January 2004 newsletter). ATLAS is coordinated by CTSU at the University of Oxford, England, but involves collaborators world-wide. It is already established that about five years of tamoxifen provides a definite improvement in long-term survival and reduces the risk of recurrence and of developing a new cancer in the opposite breast. However, there is uncertainty about the optimal duration of tamoxifen and whether a woman should stop her tamoxifen after a few years or continue for several years longer (Lancet 2005; 365:1687-1717). With several million women now taking adjuvant tamoxifen, this question is of major importance and can only be addressed reliably through large-scale randomised evidence. The main focus of ATLAS is to establish whether 10 years of tamoxifen confers greater benefit overall than just 5 years of the same treatment. The results from ATLAS in combination with the other smaller trials of the same question (see page 2 of the January 2005 newsletter) will affect the management of hundreds of thousands of women worldwide and potentially could avoid several thousands of unnecessary deaths, and although this is a study of tamoxifen duration, its results will be relevant to the appropriate duration of other, newer, hormonal treatments. ATLAS started in the mid 1990s, completed accrual in March 2005 with over 15,000 women randomised and is now in the follow-up phase. The principal analysis in ATLAS will be of all-cause mortality, complemented by subsidiary analyses of deaths from specific causes. The incidence of second primary tumours and of major events requiring hospitalisation will also be examined. ATLAS is the largest breast cancer treatment trial ever undertaken, and makes up around 2/3 of the world-wide randomised evidence in trials of 10 versus 5 years of adjuvant tamoxifen. The preliminary results from ATLAS are set out in the latest ATLAS newsletter (November 2010) along with plans for publication and the long-term follow-up on all ATLAS patients, which will continue until 2015.


Links to relevant sites

ATLAS was designed and is coordinated by the Clinical Trial Service Unit at Oxford University, under the overall direction of Dr Christina Davies.