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EBCTCG publications and findings

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2025

Extending the duration of endocrine treatment for early breast cancer: patient-level meta-analysis of 12 randomised trials of aromatase inhibitors in 22 031 postmenopausal women already treated with at least 5 years of endocrine therapy Lancet 2025: 406: 603-614 DOI: 10.1016/S0140-6736(25)01013-X 

Report on 22 031 postmenopausal women entering randomised trials of further endocrine therapy using aromatase inhibitors after at least five years of endocrine therapy for ER-positive disease found that further therapy reduced the risk of distant recurrence; in particular for those who had received 5 years of aromatase inhibitors, a further 5 years of aromatase inhibitor treatment reduced distant recurrence risks by about a quarter. 

2024 

Reductions in recurrence in women with early breast cancer entering clinical trials between 1990 and 2009: a pooled analysis of 155 746 women in 151 trials Lancet 2024; 404: 1407-1418 DOI: 10.1016/S0140-6736(24)01745-8 

Report on 155,746 women entering randomised trials of breast cancer treatment between 1990 and 2009 found that outcomes in these women had improved markedly. About 80-90% of the improvement in outcomes could be explained by changes in the types of women entering clinical trials, and by improvements in therapy over this period. 

2023 

Radiotherapy to regional nodes in early breast cancer: an individual patient data meta-analysis of 14 324 women in 16 trials Lancet 2023; 402: 1991-2003 DOI: 10.1016/S0140-6736(23)01082-6 

Report on 14,000 women in 16 trials of radiotherapy to regional nodes found a difference in effectiveness of regional node radiotherapy depending on whether or not more modern radiotherapy techniques were used. There was little effect on breast cancer mortality in the earlier trials, but significantly increased late mortality from non-breast causes. Conversely, in the newer trials, there was a 13% reduction in breast cancer mortality, no effect on non-breast cancer mortality, and an overall 10% reduction in all-cause mortality. 

Anthracycline-containing and taxane-containing chemotherapy for early-stage operable breast cancer: a patient-level meta-analysis of 100 000 women from 86 randomised trials Lancet 2023; 401: 1277-1292 DOI: 10.1016/S0140-6736(23)00285-4 

Report on 100,000 women in 86 trials of anthracycline-containing and taxane-containing chemotherapy found that recurrence rates averaged 14% lower with regimens including both anthracycline and taxane compared to regimens with taxane alone. Greatest efficacy was seen using regimens with higher cumulative doses of both drugs. 

2022 

Aromatase inhibitors versus tamoxifen in premenopausal women with oestrogen receptor-positive early-stage breast cancer treated with ovarian suppression: a patient-level meta-analysis of 7030 women from four randomised trials Lancet Oncol 2022; 23: 382-92 DOI: 10.1016/S1470-2045(21)00758-0 

Report on 7000 premenopausal women in 4 trials of aromatase inhibitors versus tamoxifen for ER positive breast cancer treated with ovarian suppression showed that recurrence was reduced by about one fifth, with aromatase inhibitors as effective in women under the age of 35 as in older women. 

2021 

Trastuzumab for early-stage, HER2-positive breast cancer: a meta-analysis of 13 864 women in seven randomised trials Lancet Oncol 2021; 22: 1139-50 DOI: 10.1016/S1470-2045(21)00288-6 

Report on 13,500 women in 7 trials of trastuzumab for HER2 positive breast cancer confirmed a reduction of about one third in recurrence and breast cancer mortality from trastuzumab. Benefits were seen irrespective of patient or tumour characteristics. 

2019 

Increasing the dose intensity of chemotherapy by more frequent administration or sequential scheduling: a patient-level meta-analysis of 37 298 women with early breast cancer in 26 randomised trials Lancet 2019; 393: 1440-52 DOI: 10.1016/S0140-6736(18)33137-4 

Report on 37,000 women in 26 trials of chemotherapy dose intensification showed that increasing dose intensity (eg by 2-weekly rather than 3-weekly administration) reduced the risk of breast cancer recurrence and death. 

2018 

Long-term outcomes for neoadjuvant versus adjuvant chemotherapy in early breast cancer: meta-analysis of individual patient data from ten randomised trials Lancet Oncol 2018; 19: 27-39 DOI: 10.1016/S1470-2045(17)30777-5 

Report on 4500 women in 10 trials of neoadjuvant chemotherapy (given before surgery) versus adjuvant chemotherapy (given after surgery) showed that there was no significant difference between neoadjuvant and adjuvant chemotherapy for distant recurrence, breast cancer mortality or death from any cause. Neoadjuvant chemotherapy allowed more women to have breast-conserving therapy than adjuvant chemotherapy. However, the risk of cancer recurring in the breast or adjacent lymph glands (local recurrence) was somewhat higher in the neoadjuvant than the adjuvant chemotherapy group. This increased risk of local recurrence was greater in trials which omitted surgery in the event of a good response to neoadjuvant chemotherapy. 

2017 

20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years N Engl J Med 2017; 377: 1836-46 DOI: 10.1056/NEJMoa1701830 

Report on the 20-year risks of breast cancer recurrence after stopping endocrine therapy after 5 years showed that when endocrine therapy ended, the risk of the cancer reappearing and spreading throughout the body continued at a similar rate over at least the next 15 years. The risk depended mainly on the original cancer’s size, and the number of lymph nodes that were cancerous. But, even for those patients with the best outlook (small tumours with no spread to the lymph nodes), there was a 10% chance of cancer spread 20 years after the initial diagnosis, sufficient for further endocrine therapy to be at least considered 

Estimating the risks of breast cancer radiotherapy: evidence from modern radiation doses to the lungs and heart and from previous randomized trials J Clin Oncol 2017; 35: 1641-49 DOI: 10.1200/JCO.2016.72.0722 

Report on the risks of breast cancer radiotherapy included more than 40,000 women in 75 randomised trials and showed that late side-effects of modern radiation therapy for breast cancer depend largely on a woman’s smoking status. For non-smokers, the absolute risks of lung cancer and heart disease from modern radiation therapy were <1%. But for long-term continuing smokers they were close to 5%, which may outweigh the benefit. Stopping smoking at the time of radiotherapy may avoid much of this risk.  

2015 

Adjuvant bisphosphonate treatment in early breast cancer: meta-analyses of individual patient data from randomised trials Lancet 2015; 386: 1353-61 DOI: 10.1016/S0140-6736(15)60908-4 

Report on 20 000 women in 26 randomised trials of bisphosphonates, showed that 2–5 years of treatment with these drugs, which are usually used to treat osteoporosis, reduces the risk of breast cancer recurring in the bones, and significantly extends survival. However, bisphosphonate treatment appears effective only for post-menopausal women and had little effect in premenopausal women. 

Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials Lancet 2015; 386: 1341-52 DOI: 10.1016/S0140-6736(15)61074-1 

Report on 30 000 postmenopausal women in 9 randomised trials comparing aromatase inhibitors (AIs) with tamoxifen, showed that 5 years of treatment with an AI produces even better survival than five years of tamoxifen. Compared to tamoxifen, taking AIs for five years further reduced the likelihood of the cancer recurring by 30%, and the risk of dying from breast cancer by around 15%. Thus taking an AI for 5 years, compared to no endocrine treatment, would reduce the risk of dying from breast cancer by around 40% in the decade after starting treatment. 

2014 

Effect of radiotherapy after mastectomy and axillary surgery on 10-year recurrence and 20-year breast cancer mortality: meta-analysis of individual patient data for 8135 women in 22 randomised trials Lancet 2014; 383: 2127-35 DOI: 10.1016/S0140-6736(14)60488-8 

Lancet report showed that after mastectomy and axillary clearance radiotherapy reduced breast cancer recurrence and mortality not only in women whose breast cancer had spread to many lymph nodes but also in those with spread to only 1-3 axillary lymph nodes. 

2012 

Comparisons between different polychemotherapy regimens for early breast cancer: meta-analyses of long-term outcome among 100 000 women in 123 randomised trials Lancet 2012; 379: 432-44 DOI: 10.1016/S0140-6736(11)61625-5 

2011/12 Lancet reports updated evidence from 2005, bringing together data from 100,000 women in 123 randomised trials of chemotherapy, showing that chemotherapy can reduce breast cancer mortality not only in ER-negative but also in ER-positive disease, and showing benefits of taxane-based over standard anthracycline chemotherapy. 

2011 

Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10 801 women in 17 randomised trials Lancet 2011; 378: 1707-16 DOI: 10.1016/S0140-6736(11)61629-2 

Report on radiotherapy after breast-conserving surgery showed that radiotherapy halves the rate at which the disease recurs and reduces the breast cancer death rate by about a sixth. 

Relevance of breast cancer hormone receptors and other factors to the efficacy of adjuvant tamoxifen: patient-level meta-analysis of randomised trials Lancet 2011; 378: 771-84 DOI: 10.1016/S0140-6736(11)60993-8 

Report on 20 000 women in 20 randomised trials of about 5 years of tamoxifen versus no tamoxifen, showed a highly significant reduction of about a third in breast cancer mortality not only during years 0-4 and 5-9 after starting treatment but also during years 10-14. Tamoxifen is effective whether or not chemotherapy has been given and, importantly, even in weakly ER positive disease. 

2010 

Overview of the randomized trials of radiotherapy in ductal carcinoma in situ of the breast J Natl Cancer Inst Monogr 2010; 41: 162-77 DOI: 10.1093/jncimonographs/lgq039 

Report on 3279 women in 4 trials of radiotherapy versus no radiotherapy for DCIS showed a highly significant reduction of ipsilateral breast event (either recurrent DCIS or invasive cancer). 

2008 

Adjuvant chemotherapy in oestrogen-receptor-poor breast cancer: patient-level meta-analysis of randomised trials Lancet 2008; 371: 29-40 DOI: 10.1016/S0140-6736(08)60069-0 

Report on 6000 women in 46 trials of chemotherapy versus not, and 14,000 women in 50 trials of tamoxifen versus not found a significant reduction in recurrence in women with ER-negative disease, while tamoxifen had little effect.  

2005 

Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials Lancet 2005; 366: 2087-106 DOI: 10.1016/S0140-6736(05)67887-7 

Report on surgery and radiotherapy showed that regimens that substantially reduce 5-year local recurrence rates have little effect on 5-year breast cancer mortality, but moderately reduce 15-year breast cancer mortality. 

Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials Lancet 2005; 365: 1687-717 DOI: 10.1016/S0140-6736(05)66544-0 

Lancet report on systemic therapies showed the substantial effects on 15-year survival of the chemotherapy regimens (eg, about 6 months of anthracycline-based chemotherapy) and endocrine regimens (eg, 5 years of tamoxifen) that were being tested in the 1980s.