Supplementary Material for: Overall survival in metastatic breast cancer patients: Real world data from 1000 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 1000 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. Fourteen % of patients presented with triple-negative, 20% with HER2-positive, and 66% with hormone receptor-positive, HER2-negative mBC. Median OS was 31.7 month. 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 years 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 prospective real-world analysis of 1000 mBC patients demonstrated significant OS differences, emphasizing the importance of personalized treatment approaches.