Association of triple positivity with prognostic parameters and overall survival in a population-based study of 6,122 HER2-positive breast cancer patients: analysis of real-world clinical practice based on a research database

Iveta Kolarova, Jaroslav Vanasek, Martin Dolezel, Jan Stuk, Ales Hlavka, Ladislav Dusek, Bohuslav Melichar, Tomas Büchler, Ales Ryska, Jana Prausova, Katarina Petrakova, Petra Tesarova, Jiri Petera, Milan Vosmik, Katerina Horackova,  Jiri Jarkovsky

Abstract:

Triple-positive breast cancer (TPBC), i.e. HER2-positive (HER2+) and hormone receptors-positive breast cancer, is a specific subgroup of breast cancers. TPBC biology is characterized by strong mutual interactions between signaling pathways stimulated by estrogens and HER2 amplification. The present study aims to carry out a population-based analysis of treatment outcomes in a cohort of hormone receptor (HR) positive and negative breast cancer patients who were treated with anti-HER2 therapy in the Czech Republic. The BREAST research database was used as the data source for this retrospective analysis. The database covers approximately 95% of breast cancer patients treated with targeted therapies in the Czech Republic. The analysis included 6,122 HER2-positive patients. The patients were divided into two groups, based on estrogen receptor (ER) or progesterone receptor (PR) positivity: hormone receptor negative (HR-) patients had both ER- and PR-negative tumors (n=2,518), unlike positive (HR+) patients (n=3,604). HR+ patients were more often diagnosed premenopausal at the time of diagnosis, presented more often at stage I or II and their tumors were less commonly poorly differentiated. The overall survival (OS) was significantly higher in subgroups of HR+ patients according to treatment setting. When evaluated by stages, significantly higher OS was observed in HR+ patients diagnosed at stages II, III, and IV and regardless of tumor grade.