Correlation between changes in 2- or 3-year disease-free survival (DFS) and 5-year overall survival (OS) in adjuvant breast cancer trials from 1966–2006

581 Background: Although disease-free survival (DFS) is accepted as a valid endpoint in adjuvant breast cancer trials, improvement in 2- or 3-year DFS has never been formally established as an adequate surrogate for 5- or 10-year overall survival (OS). We set out to establish if changes in 2- or 3-year DFS can be used to accurately predict changes in 5- or 10-year OS. Method: We conducted a systematic Medline search for phase …