Overall Survival in Metastatic Breast Cancer Patients: Real-World Data from 1,000 Patients Treated at the NCT Heidelberg between 2014 and 2022.

Introduction: In recent years, targeted therapeutic options for metastatic breast cancer (mBC) have improved significantly. In this analysis, we evaluated overall survival (OS) data of a prospectively documented cohort of 1,000 patients with mBC treated at the NCT Heidelberg from 2014 to 2022. Patients and Methods: Clinical data were prospectively collected and documented in the Prospective Academic Translational Research PRAEGNANT Network. OS was analyzed according to molecular subtype and line of therapy at study entry. We further evaluated the clinical characteristics associated with long-term (>5 years) and short-term (<1 year) survival. Results: The median age at first diagnosis of metastasis was 57 years. A total of 132 patients (13%) presented with triple-negative, 189 (19%) with HER2 positive, and 609 (61%) with hormone receptor-positive, HER2-negative mBC. Median OS was 31.7 months. The longest median OS was observed in patients with HER2-positive and luminal A-like mBC (42 and 39 months, respectively). Patients with luminal B-like and triple-negative mBC showed significantly shorter OS (21 and 14 months, respectively). In univariable Cox regression analysis, significantly shorter OS was associated with higher tumor grade; negative estrogen receptor (ER), progesterone receptor (PR), and HER2 status; triple-negative molecular subtype; use of (neo)adjuvant chemotherapy; and later line of therapy at study entry. Multivariable Cox regression analysis revealed that higher tumor grade, negative ER and HER2 status, triple-negative or luminal B-like tumor biology, and study entry during later lines of therapy were the main risk factors for shorter OS. At 5-year follow-up, 17% of patients were still alive. Long-term survivors (>5 years) were more frequently ER, PR, and HER2 positive, received less often (neo)adjuvant chemotherapy, and had a longer disease-free interval. Conclusion: This single-center, real-world analysis of 1,000 mBC patients revealed significant OS differences across molecular subtypes and provided valuable information on prognostic factors. These findings underscore the impact of tumor biology and the need for personalized treatment approaches.