Improvement in Breast Cancer Survival Across Molecular Subtypes in Hungary Between 2011-2020: a Nationwide, Retrospective Study

Miklós Darida ¹ Gábor Rubovszky ² Zoltán Kiss ^1,3* Borbála Székely ² Balázs Madaras ² Zsolt Horváth ⁴ Judit Kocsis ⁴ István Sipőcz ⁵ Máté Várnai ¹ Éva Balogh ¹ Krisztina Andrea Kovacs ¹ Viktória Buga ¹ Eugenia Karamousouli ⁶ Geza Tamas Szabo ¹ György Rokszin MD ⁷ Ibolya Fábián ^7,8 István Kenessey ^10,9 Andras Weber ¹⁰ Peter Nagy ^11,12,13 Zsófia Barcza ¹⁴ Krisztina Bogos ¹⁵ Zoltán Vokó ^16,17 Csaba Polgár ^18,19

• ¹ MSD Pharma Hungary Ltd, Budapest, Hungary
• ² Department of Oncological Internal Medicine and Clinical Pharmacology "B" and National Tumor Biology Laboratory, Budapest, Hungary
• ³ Second Department of Medicine and Nephrology-Diabetes Centre, University of Pécs Medical School, Pécs, Hungary
• ⁴ Department of Oncology, Bács-Kiskun County Teaching Hospital,, Kecskemét, Hungary
• ⁵ Aladár Petz County University Teaching Hospital, Győr, Hungary
• ⁶ MSD Greece, Alimos, Greece
• ⁷ RxTarget Ltd, Szolnok, Hungary
• ⁸ University of Veterinary Medicine Budapest, Budapest, Hungary
• ⁹ Department of Pathology, Forensic and Insurance Medicine, Semmelweis University, Budapest, Hungary
• ¹⁰ Hungarian National Cancer Registry and National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary
• ¹¹ Department of Molecular Immunology and Toxicology and the National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary
• ¹² Department of Anatomy and Histology, HUN-REN–UVMB Laboratory of Redox Biology Research Group, University of Veterinary Medicine, Budapest, Hungary
• ¹³ Chemistry Institute, University of Debrecen, Debrecen, Hungary
• ¹⁴ Syntesia Medical Communications Ltd, Budapest, Hungary
• ¹⁵ National Korányi Institute of Pulmonology, Budapest, Hungary
• ¹⁶ Center for Health Technology Assessment, Semmelweis University, Budapest, Hungary
• ¹⁷ Syreon Research Institute, Budapest, Hungary
• ¹⁸ National Institute of Oncology, Budapest, Hungary
• ¹⁹ Department of Oncology, Semmelweis University, Budapest, Hungary

Background: Despite well-documented clinical differences across breast-cancer (BC) molecular subtypes and relevant changes in therapeutic interventions over the past decades, there remains a significant lack of up-to-date epidemiologic data and real-world outcomes, particularly in Central and Eastern Europe.Methods: This was a nationwide, retrospective study using the claims databases of the Hungarian National Health Insurance Fund (NHIF) that included patients who were newly diagnosed with BC between 2011 and 2020. BC subtypes were defined based on the therapies received. Overall survival (OS) and net survival rates were calculated.Results: Between 2011 and 2020, 74,143 patients were newly diagnosed with BC based on ICD-10 diagnostic codes in the NHIF database and 80.1% of the cases could be classified into subtypes based on therapy. The most common subtype was HER2-/HR+ BC, identified in 61.9% of patients, followed by triple negative breast cancer (TNBC) in 8.4%, HER2+/HR+ BC in 6.2%, and HER2+/HR-BC in 3.6% of cases. The proportions of TNBC and HER2+/HR+ were higher among younger patients, than in elderly cohorts. The 5-year OS of the total BC population was 74.2% in patients diagnosed between 2015-2019. Patients with TNBC had the poorest 5-year OS (TNBC: 61.4%; HER2+/HR+: 86.5%; HER2-/HR+: 79.1%; HER2+/HR-: 71.9%). Net survival rates (i.e. survival rates after adjusting the effects of other causes of death) varied across diagnostic periods and molecular subtypes. In most cases, patients diagnosed later during the study period tended to have numerically better survival rates. Patients with HER2-/HR+ BC had the most favorable net survival, with 5-year net survival exceeding 92% during the whole observation period, while TNBC patients had the lowest 5-year net survival rates ranging between 63.6% and 65.8% during the study period.Our nationwide study describes the distribution and survival of BC patients with different subtypes based on a retrospective analysis of the health insurance fund database. There remains a significant room for improvement in the survival of more aggressive molecular subtypes including HR-/HER2+ and triple-negative BC, which are more common in younger age cohorts.