Impact of Adverse Events on Health Utility and Health-Related Quality of Life in Patients Receiving First-Line Chemotherapy for Metastatic Breast Cancer: Results from the SELECT BC Study

Objective: The aim of this study was to investigate the impact of adverse events (AEs) on health utility and health-related quality of life (HRQOL) in patients with metastatic breast cancer undergoing first-line chemotherapy. Methods: We analyzed the data from the SELECT BC study, a multicenter, open-label, randomized, phase III study conducted in Japan, which compared first-line S-1 with taxane therapies. Heath utility and HRQOL were assessed using the EQ-5D-3L and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) at baseline and 3, 6, and 12 months after treatment initiation. Health utility was calculated based on societal preferences, and AEs were reported at each cycle of the study treatment. Linear marginal mean models were used to quantify the impact of the last AEs (with 10 or more incidences) observed before HRQOL assessment on health utility and HRQOL. Results: Analysis included 380 patients and 12 (of 15) AEs. Grade 1 nausea and oral mucositis, grade 1 and 2 edema, and grade 2 fatigue, motor and sensory neuropathy, and myalgia were significantly associated with disutility, measured using the EQ-5D-3L. Grade 1 oral mucositis, grade 1 and 2 fatigue, and grade 2 sensory neuropathy were significantly associated with impaired global health status in the EORTC QLQ-C30. AEs associated with decrements in the five functioning scales included fatigue, oral mucositis, nausea, edema, motor and sensory neuropathy, and myalgia. Conclusions: We reported disutilities caused by AEs in patients with metastatic breast cancer under chemotherapy. These findings can be applied to future model-based cost-effectiveness analyses. Trial Registration Number: C000000416.