The Difference In Prognostic Outcomes Between De Novo Stage Iv And Recurrent Metastatic Patients With Hormone Receptor-Positive, Her2-Negative Breast Cancer

Background/Aim: Patients with de novo stage IV and recurrent metastatic breast cancer are often treated with the same strategies, although the difference in prognostic outcomes remains unclear. The objective of this retrospective chart review study was to compare the prognostic outcomes between two types of patients with hormone receptor-positive (HR+), HER2-negative (HER2-) breast cancer. Patients and Methods: We estimated overall survival of the two groups and evaluated the progressive course of the disease using disease-free interval (DFI) and interval from the end of adjuvant treatment to the first recurrence (AFI). Results: We studied 172 patients with HR+/HER2-breast cancer, of which 65 were de novo and 107 were recurrent. Median OS between de novo and recurrent BC was 4.85 and 3.45 years, respectively (p=0.046). Recurrent patients with a DFI< 2 years were found to have a significantly poorer prognosis than recurrent patients with a DFI >= 2 years (p=0.016) and de novo patients (p=0.002). Similarly, recurrent patients with an AFI< 1 year had a significantly poorer prognosis compared to de novo patients (p=0.026). Conclusion: De novo patients had better prognoses than recurrent patients with DFI< 2 years or AFI< 1 year, likely due to their therapynaive status or lower resistance to systemic treatment.