Treatment patterns and clinical outcomes in patients with metastatic triple-negative breast cancer: a large-scale data analysis using the Japanese claims database

This study evaluated treatment patterns and clinical outcomes among patients with metastatic triple-negative breast cancer (mTNBC) in real-world clinical settings in Japan. The treatment patterns, time to next treatment or death (TTNTD), time to treatment discontinuation, adverse events of interest, and medical costs of treating patients with mTNBC in first-, second-, and third-line settings were investigated using data of patients meeting the inclusion criteria between January 2017 and March 2022 in a Japanese medical claims database. The treatment regimens for mTNBC were defined according to the Japanese Breast Cancer Society Clinical Practice Guidelines. In this study, 2236 patients with mTNBC (median age 66.0 years; 99.8