Background: The "EMERGE" study, aimed to capture real-life management patterns and outcomes in metastatic breast cancer (MBC) in Greece, also accounting for hormone (HR) and human epidermal growth factor receptor 2 (HER2) status.
Methods: "EMERGE" was a multicenter, retrospective cohort study of adult MBC patients diagnosed between 01-Janaury-2010 and 30-June-2012, either de novo or having progressed from a non-metastatic state. Patient data, including treatment patterns and outcomes, were mainly abstracted through medical chart review.
Results: 386 patients were enrolled by 16 hospital-based oncologists between 12-March-2013 and 31-March-2015. The median look-back period was 29.1 months. At MBC diagnosis, 56.1% of the patients were HR+/HER2-, 16.6% HR+/HER2+, 14.5% HR-/HER2-, and 12.8% HR-/HER2+. In the first line setting, chemotherapy, targeted therapy and endocrine therapy were received by 76.7, 52.4, and 28.3% of the overall population, and by 66.5/36.2/42.0%, 80.4/80.4/28.6%, 88.4/90.7/0.0, and 95.6%/56.5/6.5% of the HR+/HER2-, HR+/HER2+, HR-/HER2+, HR-/HER2- subpopulations, respectively. In the overall population, the disease progression incidence rate was 0.57 [95% confidence interval (CI): 0.48-0.67] per person-year; median progression-free survival (PFS) was 22.4 (95% CI: 20.4-24.7) and overall survival (OS) was 45.0 (95% CI: 40.9-55.0) months. Median PFS was 24.6 (95% CI: 21.3-27.9) in HR+/HER2-, 19.7 (95% CI: 12.9-25.9) in HR+/HER2+, 23.0 (95% CI: 16.6-29.7) in HR-/HER2+ and 18.3 (95% CI: 10.0-24.7) months in HR-/HER2- subpopulations. A multivariable Cox proportional hazards model, adjusted among other factors for age and duration of diagnosis, HR and HER2 status, demonstrated that in the overall population PFS was better among those receiving first line endocrine therapy (hazard ratio: 0.70; 95%CI: 0.51-0.95; p = 0.024).
Conclusions: "EMERGE" demonstrates differences between HR/HER2 subtypes in clinical outcomes and divergence from evidence-based guideline recommendations for MBC management, especially as it pertains to the HR+/HER2- patients in which chemotherapy was favored over endocrine therapy in the first line setting.
Study registration: The study has been registered on the electronic Registry of Non-Interventional Studies (RNIS) posted on the website of the Hellenic Association of Pharmaceutical Companies (SFEE): https://www.dilon.sfee.gr/studiesp_d.php?meleti_id=NIS-OGR-XXX-2012/1.
Keywords: Greece; Hormone receptor; Human epidermal growth factor receptor 2; Metastatic breast cancer; Overall survival; Progression-free survival; Treatment patterns.