Time trends in real-world treatment patterns and survival in patients diagnosed with de novo HER2+ metastatic breast cancer: an analysis of the SONABRE registry

The aim was to determine whether the real-world first-line progression-free survival (PFS) of patients diagnosed with de novo human epidermal growth factor receptor 2 positive (HER2+) advanced breast cancer (ABC) has improved since the introduction of pertuzumab in 2013. In addition to PFS, we aimed to determine differences in overall survival (OS) and the use of systemic and locoregional therapies. Included were patients systemically treated for de novo HER2+ ABC in ten hospitals in 2008–2017 from the SONABRE Registry (NCT-03577197). First-line PFS and OS in 2013–2017 versus 2008–2012 was determined using Kaplan–Meier analyses and multivariable Cox proportional hazards modelling. First-given systemic therapy and the use of locoregional therapy within the first year following diagnosis were determined per period of diagnosis. Median and five-year PFS were 26.6 months and 24