Relevance of breast cancer hormone receptors and other factors to the efficacy of adjuvant tamoxifen: patient-level meta-analysis of randomised trials
- Study type
- Meta-analysis
- Study name
- EBCTCG tamoxifen 2011
- Design
- Collaborative patient-level meta-analysis of randomised trials
- Sample size
- 21,457 patients in 20 trials (of whom 10,645 had ER-positive disease)
- Source
- The Lancet · 2011
In plain words
This study brought together information on more than 21 thousand women with early breast cancer from 20 trials. The result showed that taking tamoxifen for about 5 years, in women whose tumour is oestrogen receptor-positive, lowers the risk of the cancer coming back and of death from breast cancer over the next 15 years by about a third. In oestrogen receptor-negative tumours, the drug has almost no effect. The absolute benefit for each patient depends on her starting risk of the cancer coming back; make the decision with your treating doctor.
Key results
Treatment arms and regimens
About 5 years of tamoxifen.
Meta-analysis of multiple trials; dose and schedule varied between trials and no single dose is reported.
No adjuvant tamoxifen.
Source of the regimen details: Abstract of the paper
Doses are given for the information of specialists, as in this study’s protocol, and are not a prescription. Every drug must be prescribed by the treating physician for the individual patient.
Study population
Women with early breast cancer in 20 trials comparing about 5 years of tamoxifen with no adjuvant tamoxifen. Treatment adherence was about 80%. Further details of the inclusion criteria are in the full text.
Endpoints
Rate ratios (RR) for recurrence and death, from log-rank analyses by allocated treatment. Recurrence, breast cancer death, non-breast-cancer death and death from any cause were examined by oestrogen receptor (ER) status and other factors.
Safety and side effects
Non-breast-cancer mortality was little affected overall, although a small absolute increase in deaths from thromboembolism and uterine cancer was seen (both only in women older than 55 years). All-cause mortality was therefore substantially reduced.
Clinical significance and place in guidelines
This meta-analysis shows that ER status is the only recorded factor that importantly predicts the proportional risk reduction with tamoxifen; progesterone receptor, age, nodal status and chemotherapy had no marked effect on the proportional reduction. No benefit was seen in ER-negative disease, and even in weakly ER-positive disease the reduction in recurrence was substantial. The absolute risk reduction depends on the absolute risk without tamoxifen. The exact status of these findings in current guidelines should be checked.
Limitations
According to the abstract, treatment adherence was about 80% and analyses were by allocated treatment. The meta-analysis is limited to trials of about 5 years of tamoxifen versus no treatment. Other limitations should be checked in the full text.
This summary was prepared by the editorial team from the published paper; the original paper is the final reference. Read the original abstract on PubMed.