Landmark and milestone survival (5-year survival, median follow-up)

Kaplan-Meier curves show the proportion of patients event-free over time; the median is the point where the curve crosses 50%, and landmark rates are read at fixed times. Medians can mislead when curves plateau (a durable tail after checkpoint inhibitors or CAR-T) or cross (delayed immunotherapy benefit), so milestone rates and restricted mean survival time supplement hazard ratios. Landmark analyses also compare outcomes from a fixed time conditional on status at that time (e.g. survival by MRD status at 12 months), avoiding immortal-time bias. Median follow-up indicates how mature the data are; 5-year rates need at least 5 years of follow-up in a reasonable number of patients to be reliable.