Abstract 201P
Background
This study aims to determine whether real-world overall survival (OS) of patients diagnosed with de Novo human epidermal growth factor receptor 2 positive (HER2+) advanced breast cancer (ABC) improved in the Netherlands since the introduction of pertuzumab in 2013.
Methods
Patients systemically treated for de Novo HER2+ ABC in 2008-2017 were retrieved from the Netherlands Cancer Registry. Vital status was obtained on January 31, 2023. OS was estimated using the Kaplan-Meier method and compared between 2013-2017 and 2008-2012 through multivariable Cox proportional hazards modelling. The use of first-given HER2-targeted therapy was determined per period. Analyses were stratified for age, grade, hormone receptor status, number of organs with metastases, initial metastatic sites, and surgery of the primary tumour.
Results
Among 1, 458 systemically treated patients, OS was longer for patients diagnosed in 2013-2017 than in 2008-2012 (five-year OS rates were 46% versus 31%, adjusted hazard ratio=0.67, 95% confidence interval:0.59-0.76, p<0.001). OS improved for all subgroups except for patients with central nervous system (CNS) metastases. First-given HER2-targeted therapy was received by 88% of patients in 2013-2017 and 72% in 2008-2012. Pertuzumab use in 2013-2017 was 50%, which increased from 9% in 2013 to 76% in 2017. Pertuzumab use was highest in patients aged <50 years (63%) and lowest in patients aged ≥75 years (19%).
Conclusions
OS has improved by 33% in Dutch patients with de Novo HER2+ ABC 2013-2017 versus 2008-2012. This advancement was observed in all subgroups except for patients with CNS metastases. The implementation of pertuzumab was slow and deserves attention.
Legal entity responsible for the study
Maastricht University Medical Center.
Funding
Has not received any funding.
Disclosure
K.E.P.E. Hermans: Financial Interests, Institutional, Funding: Novartis BV, AstraZeneca, Gilead. M. De Boer: Financial Interests, Institutional, Funding: Novartis BV, Roche, Pfizer, Eli Lilly, Daiichi Sankyo, Gilead, AstraZeneca. T.J.A. van Nijnatten: Financial Interests, Institutional, Funding: Bayer; Financial Interests, Personal, Invited Speaker: Bayer, GE Healthcare. D. Lobbezoo: Financial Interests, Institutional, Funding: Novartis BV, Roche, Pfizer, Eli Lilly, Daiichi Sankyo, Gilead, AstraZeneca. V.C.G. Tjan-Heijnen: Financial Interests, Institutional, Funding: Roche, Novartis, Pfizer, Eli Lilly, AstraZeneca, Eisai, Daiichi Sankyo, Gilead; Financial Interests, Personal, Funding: Roche, Novartis, Pfizer, Eli Lilly, Accord Healthcare. S.M.E. Geurts: Financial Interests, Institutional, Funding: Novartis BV, Roche, Pfizer, Eli Lilly, Daiichi Sankyo, Gilead, AstraZeneca; Financial Interests, Personal, Funding: AstraZeneca. All other authors have declared no conflicts of interest.