Currently the recommendations is to give adjuvant tamoxifen for 5 years. A study that was presented at the San Antonio Breast Cancer Symposium and published simultaneously in The Lancet, showed that extending tamoxifen treatment to 10 years was superior than 5 years. Giving tamoxifen for 10 years reduced the risk of dying from breast cancer by almost one third.
Adjuvant Tamoxifen–Longer Against Shorter (ATLAS) enrolled 6,846 women and was conducted in 36 countries between 1996 and 2005. All women were diagnosed with estrogen receptor–positive breast cancer and had taken Tamoxifen for 5 years. About half of the women were randomly assigned to continue with 5 more years of tamoxifen (10 years total) and the other half to no more tamoxifen.
After 10 to 14 years of diagnosis there were 617 recurrences of cancer in the group taking 10 years of tamoxifen versus 711 recurrences in patients treated with 5 years of tamoxifen.
After 5 to 14 years of diagnosis the risk of dying from breast cancer was 12.2% for the 10-years users compared with 15.0% for the 5-year users.
The greatest benefit was seen after 10 to 14 years after diagnosis; women who took tamoxifen for 10 years had a 25% less risk of the cancer coming back and 29% lower risk of dying from breast cancer compared with those who had only 5 years of tamoxifen therapy.
- Ten years of adjuvant tamoxifen extends survival in women who took ten year of tamoxifen compared to five years.
- The benefit of ten years tamoxifen was seen 10 to 14 years after diagnosis.
- The benefits of survival outweigh the risks, such as the small increase in endometrial cancer.
Take Home Message
- The results of ATLAS should be discussed in women who are candidate for adjuvant hormonal treatment.
1. Davies C, Pan H, Godwin J, et al, for the Adjuvant Tamoxifen: Longer Against Shorter (ATLAS) Collaborative Group: ATLAS—10 v 5 years of adjuvant tamoxifen in ER+ disease: Effects on outcome in the first and in the second decade after diagnosis. 2012 San Antonio Breast Cancer Symposium. Abstract S1-2. Presented December 5, 2012.
2. Davies C, Pan H, Godwin J, et al, for the Adjuvant Tamoxifen: Longer Against Shorter (ATLAS) Collaborative Group: Long-term effects of continuing adjuvant tamoxifen to 10 years versus stopping at 5 years after diagnosis of oestrogen receptor-positive breast cancer: ATLAS, a randomised trial. Lancet. December 5, 2012.