A nationwide observational study in heavily pretreated metastatic HER2-positive breast cancer patients. (1st February 2023)

• Record Type: Journal Article
• Authors: Due, Asbjørn; Berg, Tobias; Jensen, Maj-Britt; Yammeni, Sophie; Volmer, Lone; Brems-Eskildsen, Anne Sofie; Andersen, Klaus Kaae; Rana, Saeeda; Knoop, Ann; Kümler, Iben
• Is Part Of: Acta oncologica. Volume 62:Number 2(2023)
• Page Start: 126
• Page End: 133
• Publication Date: 2023-02-01
• Subjects: T-DM1 -- breast cancer -- overall survival -- metastatic -- HER2-positive; Oncology -- Periodicals; Cancer -- Treatment -- Periodicals; 616.992
• DOI: 10.1080/0284186X.2023.2176257
• Languages: English
• ISSNs: 0284-186X

Abstract

Abstract: Background: Current guidelines in HER2-positive metastatic breast cancer (mBC) recommend the combination of trastuzumab and a chemotherapeutic agent for 3rd line or later treatments. This study aims to describe the treatment of HER2-positive mBC in 3rd line or later after previous treatment with T-DM1 for mBC in a real-world setting. Material and methods: This observational population-based study included all women diagnosed with HER2-positive mBC in Denmark, previously treated with T-DM1 in the metastatic setting. Patients were included on the date of progression leading to initiation of 3rd line treatment if the patient had received T-DM1 in 1st or 2nd line. If the patient received T-DM1 in 3rd line or later the inclusion was based on the date of progression on T-DM1. The primary end points were overall survival (OS) and progression-free survival (PFS). Results: The study included 272 women with a mean age of 59 (27–86) and a median of 3 (2–11) treatment lines prior to inclusion. At index, all patients had received T-DM1 and 167 (62%) patients had received pertuzumab in the metastatic setting. During follow-up 183 patients received chemotherapy. Of these patients, 120 received chemotherapy combined with trastuzumab, 50 received chemotherapy combined with other HER2-targeted therapy, and 13 received chemotherapy as monotherapy. The remaining 89 patients received either HER2-targeted monotherapy (41), endocrine therapy (31), experimental treatment (10), or no treatment (7). Median PFS was 5.5 months (95% CI, 4.8–6.5) and median OS was 18.5 months (95% CI, 16.2–21.3). Conclusion: In this real-world study, we found that patients were treated with a wide variety of anti-cancer agents with modest efficacy. However, patients in this study did not have access to newer therapies like tucatinib and T-DXd.