Efficacy of Fulvestrant in Women with Hormone-Resistant Metastatic Breast Cancer (mBC): A Canadian Province Experience

Introduction: Fulvestrant has demonstrated efficacy in hormone receptor positive (HR+) metastatic breast cancer (mBC), both first-and second-line settings. In clinical practice, however, fulvestrant been used as a later-line therapy. This study assessed the of women with mBC early-versus Methods: retrospective cohort Saskatchewan HR+ who received between 2003–2019. A multivariate Cox proportional survival analysis was performed. Results: One hundred and eighty-six median age 63.5 years were identified—178 (95.6%) had hormone-resistant mBC, 57.5% visceral disease, 43.0% chemotherapy before fulvestrant. 102 (54.8%) ≤2-line-therapy, 84 (45.2%) ≥3 line-therapy The time to progression (TTP) 12 months early-treatment vs. 6 later-treatment group, p = 0.015. Overall (OS) from start 26 group 16 0.067. On analysis, absence metastasis, HR: 0.70 (0.50–0.99), significantly correlated better TTP, whereas post-fulvestrant chemotherapy, 0.32 (0.23–0.47), benefit fulvestrant, 0.44 (0.30–0.65), (0.50–0.97), OS. Conclusions: early-and therapy mBC. Our results show that or non-visceral survival.