Clinical Lead Time
Clinical lead time is an important concept leading to overestimation of survival duration among individuals in screening programs. Example: Two patients are both clinically diagnosed on the same day with cancer and go on to survive 20 years. However, if one of those patient’s had cancer detected 5 years earlier because of a screening program, and survived another 25 years, the patient in the screening program may appear to survive longer but in fact still had the identical overall survival time as the patient who did not undergo screening.
