Association between Sarcopenia and Survival in Patients Undergoing Gamma Knife Surgery for Brain Metastasis from Breast Cancer: A Retrospective Single-centre Cohort Study

Many recent studies related to cancer surgery have reported that sarcopenia influences mortality in surgical patients. However, few comprehensive studies have examined the associations between sarcopenia and short- and long-term surgical outcomes of metastatic cancer, especially breast cancer with brain metastasis. In the present study, we investigated the association between sarcopenia and mortality in patients who underwent gamma knife radiosurgery (GKRS) for brain metastasis with breast cancer. This retrospective study analysed 157 patients who underwent GKRS for brain metastasis with breast cancer between January 2014 and December 2018. A Cox regression analysis was carried out to evaluate the association between sarcopenia and mortality at 90 days, 180 days, 1 year, 3 years and the overall period. In the Cox regression analysis, sarcopenia was significantly associated with high 90-day mortality (adjusted hazard ratio 3.46, 95% confidence interval 1.24-9.67, P = 0.018), 180-day mortality (adjusted hazard ratio 2.67, 95% confidence interval 1.37-5.22, P = 0.004), 1-year mortality (adjusted hazard ratio 2.39, 95% confidence interval 1.42-4.02, P = 0.001), 3-year mortality (adjusted hazard ratio 2.39, 95% confidence interval 1.53-3.74, P < 0.001) and overall mortality (adjusted hazard ratio 2.11, 95% confidence interval 1.37-3.26, P < 0.001). Sarcopenia could be a risk factor for short- and long-term mortality in patients undergoing GKRS for brain metastasis from breast cancer.