Liu J, et al. - Considering the FALCON trial proved fulvestrant was an effective first-line endocrine therapy for post-menopause hormone receptor (HR)-positive advanced breast cancer (ABC) patients in 2016, researchers investigated the clinical and genetic risk factors for fulvestrant treatment response in real world data of 136 fulvestrant users enrolled from 2015, adopting biostatistic and bioinformatic analysis tools. As per Kaplan–Meier (KM) curves, fulvestrant first-line users had a median progression-free survival (mPFS) of 15.67 months, which was longer than the second-line users and third (or higher)-line users (mPFS = 7.47 and 5.43 months, respectively). This suggests a better prognosis for first-line fulvestrant users than higher-line users. Higher-line fulvestrant users with ESR1or ERBB2 mutation displayed poor PFS.