Patients receive TKIs after T-DM1 progression.

tyrosine kinase inhibitors based therapy

Progression-free survival estimated using Kaplan-Meier methods is defined as the time from the date of informed consent to the earlier of death or disease progression. Patients alive without disease progression are censored at the date of last disease evaluation. Progressive disease (PD) based on RECIST 1.1 is at least a 20% increase in the sum of longest diameter (LD) of target lesions taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions. Equivocal progression of non-target lesions also qualifies as PD.

The overall response rate is defined as the percentage of patients with a best overall response of CR or PR relative to the appropriate analysis set

Safety will be assessed by standard clinical and laboratory tests (haematology, serum chemistry). AE grade were defined by the NCI CTCAE (National Cancer Institute Common Terminology Criteria for Adverse Events).