Table 1. Patients’ baseline characteristics.
HER2 copy number was assessed on the primary tumors and was performed by a commercially validated assay (Foundation One; Foundation Medicine, Cambridge, MA).
Abbreviations: CEA, carcinoembryonic antigen; ECOG, Eastern Cooperative Oncology Group; HER2, human epidermal growth factor 2; NGS, next‐generation sequencing; WT, wild type.