Complete response of leptomeningeal carcinomatosis secondary to breast cancer.

Abstract Leptomeningeal carcinomatosis (LC) is an unmet medical need associated with death in 4 to 6 weeks without treatment, delayed by 4 months in some patients with favorable prognosis and aggressive multimodal therapy. Unfortunately, most clinical trials excluded patients with LC, and the best management remains unknown. Here we present the first report of a LC secondary to HR positive breast cancer with a complete response to CDK4/6 inhibitors abemaciclib, letrozole and hippocampal-avoidance whole-brain radiotherapy.