Reply to: “Inappropriate Conclusions on Surrogate End Points in Early Breast Cancer Trials” and “Methodologic Considerations in Assessing Invasive Disease-Free Survival as a Surrogate End Point for Overall Survival in Trials for Early Breast Cancer”

Fabio Conforti

Division of Medical Oncology, Humanitas Gavazzeni, Bergamo, Italy

Vincenzo Bagnardi

Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy

Isabella Sala

Fabio Conforti, MD, Division of Medical Oncology, Humanitas Gavazzeni, Bergamo, Italy, Humanitas University, Milan, Italy; Vincenzo Bagnardi, Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy; and Isabella Sala, MSc, Humanitas University, Milan, Italy, Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy