In an analysis by the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) reported in The Lancet, Hills et al found that risk of distant recurrence declined over time among women with early breast cancer enrolled in clinical trials between 1990 and 2009.
Study Details
The pooled analysis included 155,746 women from 151 trials. Rates of distant recurrence were compared for patients enrolled from 1990 to 1999 vs those enrolled from 2000 to 2009.
Key Findings
The risk of distant recurrence at 10 years for 1990–1999 vs 2000–2009 was reported as follows:
- Among node-negative patients—10.1% vs 3% in patients with estrogen receptor (ER)-positive disease and 18.3% vs 11.9% in those with ER-negative disease
- Among patients with one to three positive nodes—19.9% vs 14.7% in those with ER-positive disease and 31.9% vs 22.1% in those with ER-negative disease
- Among patients with four to nine positive nodes—39.6% vs 28.5% in those with ER-positive disease and 47.8% vs 36.5% in those with ER-negative disease.
Analysis of the improvement in risk for distant metastasis for 2000–2009 vs 1990–1999 estimated that 80.5% of the improvement for ER-positive disease and 89.8% of the improvement for ER-negative disease was attributable to changes in patient and tumor characteristics and improved treatments, including the finding that more recently diagnosed patients were more likely to have node-negative disease. However, after adjustment, the improvements remained significant (P < .0001).
After adjustment for therapy, rates of distant recurrence were reduced by 25% among patients with ER-positive disease and 19% among those with ER-negative disease over the two time periods.
The investigators concluded: “Most of the improvement in trial outcomes is explained by a greater proportion of women with lower-risk disease entering trials and improved adjuvant treatment. After adjustment, women diagnosed since 2000 have about a fifth lower rate of distant recurrence than the 1990s. Long-term risks of distant recurrence for oestrogen receptor-positive disease remain, but are about a tenth lower now than in our previous report.”
The EBCTCG Secretariat, Clinical Trial Service Unit, Nuffield Department of Population Health, Oxford, United Kingdom, is the corresponding entity for The Lancet article.
Disclosure: The study was funded by Cancer Research UK and UK Medical Research Council. For full disclosures of the study authors, visit thelancet.com.
