ATLAS: International ATLAS (Adjuvant Tamoxifen Longer Against Shorter) Breast Cancer Treatment Trial
The ATLAS started in 1995, completed randomisation in 2005 and finished trial treatment in 2010.
Follow-up is still continuing, but in 2013 the main results thus far available were published (Lancet 2013; 381: 805-16), focusing on women with oestrogen receptor positive (ER+) breast cancer who had already had about 5 years of tamoxifen. But, although these women are of particular interest, we do still need to get follow-up, preferably to about 20 years after the original diagnosis, on all women entered into ATLAS. In the 2013 Lancet report of the early ATLAS results, most of the follow-up information related to the periods 5-9 and 10-14 years after diagnosis, with little information yet available about longer-term outcomes (see figures below, which are taken from the 2013 Lancet publication).
The eventual aim is to assess the effects of 10 years of treatment on 20-year outcome. Further follow-up will consolidate the results in years 10-14 after diagnosis, and will assess the further effects during years 15-19 after diagnosis. It could well be that the added benefit of an extra 5 years of tamoxifen persists and becomes somewhat greater by year 20 than by year 15, but to establish that, we require a few more years of follow-up. In the meantime, the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) meta-analysis of the trials of 10 vs 5 years of tamoxifen will – we anticipate – be published around the end of 2016 (including ECOG, the Scottish trial, NSABP B-14, updated data from ATLAS and the new data from aTTom [the UK counterpart of ATLAS]).