ERBB2 and cancer: It waspreviously reported in a population-based study from the Netherlands that 23% ofpatients with HER2-positive cancers did not receive a trastuzumab containing regimenwhich could be partly due to the lack of registration for true EAC tumors but ispotentially related to cardiac comorbidity.32 Second, missing data on HER2status and other variables, for example, performance status, could have resulted insuboptimal adjustment of multivariable models.