ERBB2 and breast cancer: In total, 19 patients were excluded: 6 from CARMINA02 (4 staged N2 or N3 and 2 bilateral breast cancer) and 13 from HORGEN (5 HER2-positive tumours, 4 patients <65 years old with grade III tumours, 1 staged N2, 1 with distant metastases at diagnosis and 2 patients not treated) (study flowchart, Fig. 1).