ATLAS (tamoxifen)
Trial question
What are the long-term effects of continuing adjuvant tamoxifen to 10 years in female patients with ER+ breast cancer?
Study design
Multi-center
Open label
RCT
Population
12894 female patients
Inclusion criteria: female patients with ER+ early breast cancer who had completed 5 years of treatment with tamoxifen
Key exclusion criteria: contraindications to continuation of tamoxifen, pregnancy, breastfeeding, retinopathy, need for coagulation therapy, endometrial hyperplasia, other serious toxicity attributed to tamoxifen, negligibly low risk of death from breast cancer, or presence of another life-threatening disease
Interventions
N=3428 extended tamoxifen use (continuation up to 10 years)
N=3418 standard duration tamoxifen (stop at 5 years, with no placebo)
Primary outcome
Recurrent breast cancer
18
20.8
20.8 %
15.6 %
10.4 %
5.2 %
0.0 %
Extended tamoxifen use
Standard duration tamoxifen
Significant decrease ▼
NNT = 35
Significant decrease in recurrent breast cancer (18% vs. 20.8%; RR 0.84, 95% CI 0.76 to 0.94)
Secondary outcomes
Significant decrease in breast cancer death (12.2% vs. 15%; RR 0.71, 95% CI 0.58 to 0.88)
Significant decrease in death from any cause (18.6% vs. 21.1%; RR 0.87, 95% CI 0.78 to 0.97)
Significant decrease in cumulative risk of breast cancer recurrence (21.4% vs. 25.1%; RR 0.75, 95% CI 0.62 to 0.9)
Safety outcomes
No significant differences in primary liver cancer, CRC, stroke.
Significant differences in hospitalization due to pulmonary embolus (0.6% vs. 0.3%), ischemic heart disease (2.0% vs. 1.0%), and endometrial cancer (1.8% vs. 1.0%), cumulative risk of endometrial cancer during year 5-14 (3.1% vs. 1.6%).
Conclusion
In female patients with ER+ early breast cancer who had completed 5 years of treatment with tamoxifen, extended tamoxifen use was superior to standard duration tamoxifen with respect to recurrent breast cancer.
Reference
Davies C, Pan H, Godwin J et al. 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. 2013 Mar 9;381(9869):805-16.
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