Efficacy of lapatinib might be predicted by hormone receptor expression.
Lapatinib benefits human epidermal growth factor receptor 2 (HER2)+hormone receptor (HR)– early breast cancer patients not receiving trastuzumab.
When trastuzumab is not offered lapatinib might be used in HER2+HR– breast cancer.
Numbers-needed-to-treat should be presented for patient subgroups of large studies.