The coxrt package fits Cox regression based on retrospectively ascertained time-to-event
data. The method uses Inverse-Probability-Weighting (IPW) estimating equations with stabilized weights as described
in Vakulenko-Lagun, Mandel, and Betensky,
Inverse-Probability-Weighting Methods for Cox Regression with Right Truncated Data (under revision for Biometrics, 2019).
The coxrt package provides two functions: coxph.RT that assumes positivity and
coxph.RT.a0 that allows for adjustment of estimation under violation of positivity.
The coxrt package can be installed by
devtools::install_github("Bella2001/coxrt")
The examples of when and how to use coxrt package are here.