overall survival
Also written as: OS — overall survival
The primary endpoint measuring the time from treatment initiation to death from any cause.
Full Definition
Overall survival (OS) is considered the gold standard primary endpoint in oncology clinical trials, measuring the time from randomization or treatment initiation until death from any cause. Unlike disease-specific survival measures, OS captures all-cause mortality, making it an objective and unbiased measure of treatment benefit. OS data is typically presented using Kaplan-Meier survival curves and analyzed using hazard ratios. While OS is the most clinically meaningful endpoint, it often requires large sample sizes and long follow-up periods to detect significant differences between treatment arms, leading some studies to use surrogate endpoints.
Usage
Usage note: Can be abbreviated as OS. Distinguish from other survival measures that exclude non-cancer deaths.
In Context
- "The primary endpoint was overall survival at 24 months." — Clinical trial protocol
- "Median OS was significantly improved in the experimental arm (HR 0.72, p=0.003)." — Statistical analysis report