highly significantp<0·0001
Pooled analysis of all trials found a highly significant reduction in recurrence (RR 0·66, 95% CI 0·62 to 0·71; p<0·0001; figure 1 ) and breast cancer mortality (0·67, 0·61 to 0·73; p<0·0001; appendix p 7 ) with chemotherapy plus trastuzumab compared with chemotherapy alone.