Table 2.

Frequency of overdiagnosis among localized invasive screen-detected cancers corresponding to given mean lead times under two different settings for the risk of other-cause death and under three different assumptions for the lead-time distribution

Mean lead time among localized invasive breast cancers, y	Frequency of overdiagnosis among localized invasive breast cancers (percent)
	LThist*: Exponential		LThist*: Weibull (shape = 0.5)	LThist*: Weibull (shape = 2.0)
	HR† = 0.75	HR† = 0.85	HR† = 0.75	HR† = 0.75
2	3.3	4.0	3.3	3.5
4	7.0	8.2	6.9	7.3
6	11.3	13.5	10.6	11.9
8	15.5	17.3	14.1	17.0
10	20.4	21.3	16.2	20.2
12	24.3	24.9	19.5	24.4

* A Weibull distribution with shape 0.5 is more dispersed than an exponential distribution with the same mean. A Weibull distribution with shape 2.0 is less dispersed than an exponential distribution with the same mean. LTdist = lead-time distribution.

† HR = hazard ratio for other-cause death among localized invasive cases relative to the age-matched female population.