A comparison of treatment allocation and survival between younger and older patients with HER2-overexpressing de novo metastatic breast cancer.

The use of first-line chemotherapy and targeted therapy increased in all age groups, while the use of endocrine therapy decreased over time. Nevertheless, the uptake of chemotherapy and targeted therapies was substantially slower in the oldest age group. Overall survival and relative survival improved for all age groups, but these improvements were smaller in the older age groups.