Jl. Xu et al., Estimation of post-lead-time survival under dependence between lead-time and post-lead-time survival, STAT MED, 18(2), 1999, pp. 155-162
Citations number
15
Categorie Soggetti
General & Internal Medicine","Medical Research General Topics
Early detection of cancer by screening advances the date of diagnosis, but
may or may not alter time to death. Screening programme need to assess the
true benefit of screening, that is, the length of time by which survival ha
s been extended, beyond merely the time by which the diagnosis is advanced
(lead-time). One method is to estimate the distribution of the time survive
d post-lead-time using total survival time data for screen-detected cancer
cases, under the assumption of independence of the lead-time and the post-l
ead-time survival. However, it seems biologically reasonable that the lead-
time and the post-lead-time survival are positively correlated. This paper
investigates the consequences of departures from independence of lead-time
and post-lead-time survival on estimation of post-lead-time survival. We in
troduce a new model that involves dependence between the lead-time and the
post-lead-time survival. We show that the new model can be converted to the
model discussed by Xu and Prorok. We consider the non-parametric maximum l
ikelihood estimator of the post-lead-time survival under the new model. We
apply the method to data from the HIP (Health Insurance Plan of Greater New
York) breast cancer screening trial. We make comparisons with the survival
of cancer cases not detected by screening, such as interval cases, cases a
mong individuals who refused screening, and randomized control cases. Copyr
ight (C) 1999 John Wiley & Sons, Ltd.