Clinical Characteristics and Survival Outcomes of Patients with De Novo Metastatic Breast Cancer.

Purpose: Though less than 5% of patients with breast cancer present with De Novo Metastasis (dnMBC) in Western societies, this percentage may reach 30% in developing countries. In this study, we present survival outcomes of patients diagnosed with dnMBC treated at a tertiary center in a developing country. Patients and Methods: Using hospital-based database, consecutive patients with dnMBC diagnosed between 2013 and 2017 were identified. Demographic data, tumor characteristics, types of treatment, and survival data were retrospectively collected. Results: A total of 435 patients were included; median age (range) at time of diagnosis was 51 (24-85) years. Most of the tumors expressed hormone receptors (81% Estrogen Receptor positive, 77% Progesterone Receptor positive). Human epidermal growth factor receptor-2 (HER2) overexpression was reported in 134 (30.9%) patients, while only 24 (5.5%) had Triple Negative (TN) disease. Bone, lung and liver were the most common sites of metastasis involved in 70.6%, 36.1%, and 32.0%, respectively. The median Overall Survival (OS) for all patients was 38 months, and 5-year OS was 32.6%. On univariate analysis, high tumor grade, advanced T-stage, TN-disease and metastasis to multiple sites, but not HER2 status, were associated with poor OS. On multivariate analysis, high tumor grade (Hazard Ratio =1.6, p=0.002), advanced T-stage (Hazard Ratio=1.6, p=0.003), and triple negative status (Hazard Ratio= 2.1, p=0.008) predicted poor OS. Conclusion: The overall survival of patients with dnMBC remains poor. Better understanding of the disease behavior and factors affecting survival is required for optimal utilization of available regimens and new drugs to hopefully improve patients' outcomes.