Survival Benefits Associated with Surgery in Patients with Metastatic Breast Cancer by Breast Cancer Subtype

Background: Two randomized trials have examined the role of local therapy on survival in the stage IV setting of breast cancer, largely suggesting no benefit. However, the effect of surgery for stage IV disease amongst various breast cancer subtypes is not well characterized. In this study, we aimed to evaluate the survival benefit of surgery in patients with stage IV breast cancer based on molecular subtype. J Cancer Sci Clin Ther 2021; 5 (3): 414-425 DOI: 10.26502/jcsct.5079127 Journal of Cancer Science and Clinical Therapeutics 415 Methods: Using an institutional database, we extracted 255 women with a clinicopathologic confirmed diagnosis of stage IV breast cancer who were treated between January 2006 and October 2016. We collected patient data including age, clinical T stage, clinical N stage, histological grade, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and the use of radiotherapy, chemotherapy, targeted therapy and/or endocrine therapy. Correlates of overall survival (OS) and breast cancer-specific survival (BCSS) in the surgical and non-surgical groups were identified on multivariate analysis. Results: The median overall survival in the surgical group and the non-surgical group was 30.3 months and 20.7 months, respectively. There were significant differences between the two groups according to subtype in the distribution of OS and BCSS (P <0.001). On multivariate analysis for the OS and BCSS, using non-surgical group as a reference, there were significant improvement for the luminal B subtype (P=0.010). Conclusion: This study suggest that surgery of the primary breast tumor may have a positive impact on OS and BCSS in patients with stage IV breast cancer, especially in the luminal B subtype.