Your summary of the latest study by the Early Breast Cancer Trialists’ Collaborative Group states that “Even after treatment, odds of recurrence are worse for the next 20 years” (Nature http://go.nature.com/2eob74j; 2017). We find this statement unnecessarily alarming.
The same group showed in previous work that, at 15 years of follow-up, women with oestrogen-receptor-positive breast cancer who received adjuvant endocrine therapy (AET) with the drug tamoxifen for 5 years had a reduced risk of recurrence (risk reduction, 47%) and of related mortality (risk reduction, 29%). The yearly rate of death related to breast cancer also dropped by about one-third throughout the first 15 years (see Early Breast Cancer Trialists’ Collaborative Group Lancet 378, 771–784; 2011). Women with this cancer type who did not receive this treatment had a 46.2% probability of recurrence of breast cancer at 15 years.
The ATLAS randomized trial showed that extending AET with tamoxifen treatment from 5 to 10 years reduced the risk of relapse (risk reduction, 30%) and of related mortality (risk reduction, 48%) after completion of therapy. The benefits of the treatment were reaffirmed by the aTTom randomized trial (G. Schiavon and I. E. Smith Breast Cancer Res. 16, 206; 2014). These findings changed clinical practice. The American Society of Clinical Oncology guidelines now recommend that women with oestrogen-receptor-positive breast cancer should consider 10 years of AET with tamoxifen.
Nature 553, 155 (2018)