Which statement about 5-year survival is true?

• A. It represents the proportion of patients who die within five years.
• B. It represents the rate of new cases in five years.
• C. It represents the percentage of people alive five years after diagnosis or initiation of treatment.
• D. It represents the disease-free survival at five years.

Answer: (C)

Five-year survival is a survival measure that represents the percentage of people alive five years after diagnosis or initiation of treatment. It is a reflection of overall survival, counting death from any cause, and is not the proportion who die within five years, nor the rate at which new cases appear over five years (incidence). It also isn’t the same as disease-free survival, which tracks the time until recurrence or death while the disease is still a consideration. In practice, this metric is often estimated with survival analysis methods like Kaplan-Meier and can be influenced by factors such as lead-time bias from earlier detection.