ABSTRACT
Purpose@#Improving survival and health-related quality of life (HRQOL), along with symptom relief, is important for the treatment of metastatic breast cancer (MBC). This study measured HRQOL and analyzed its influence on sociodemographic and clinical factors in patients with MBC. @*Methods@#We interviewed 298 patients with MBC to investigate their sociodemographic characteristics and HRQOL by using EuroQol-5D-5L (EQ-5D) between September and October 2014. We also reviewed medical records to examine the clinical condition of the patients, including disease progression, adverse events, treatments, chronic disease, and metastatic areas. The distribution of the EQ-5D index was compared between different clinical conditions by using the Kruskal-Wallis test. We also conducted multiple regression analyses to identify the factors affecting HRQOL in patients with MBC. @*Results@#The mean EQ-5D index was 0.79 for all patients surveyed. The mean EQ-5D index score was significantly lower in patients in the progressed state than in those in the progression-free survival state (0.73 vs. 0.80, p = 0.0002). The HRQOL of patients treated with chemotherapy alone was significantly lower than that of patients treated with hormonal or targeted therapy (0.76 vs. 0.82 or 0.85; p = 0.0020). Regression analysis revealed that the clinical factors associated with lower HRQOL were progressed state, chemotherapy, and adverse events, such as hair loss or stomatitis. Finally, young age, high income, and employment were the sociodemographic factors that were positively associated with better HRQOL. @*Conclusion@#This study provides new information on the health utility of MBC patients on the basis of various patient characteristics and offers insights that can assist medical professionals in treating patients with MBC and help policymakers implement cancer strategies. Further research is needed to reflect the changing environment of cancer treatment and enrich available evidence.