Interval Censored Data Analysis for Assessing Mean Time to Cancer Relapse (51 Patients)

Abstract

In survival studies often time to first outpatient clinic check instead of time to event is measured. Somewhere in the interval between the last and current visit an event may have taken place. For simplicity such data are often analyzed using the proportional hazard model of Cox (Chap. 17, Cox regression, pp. 209–212, in: Statistics applied to clinical studies 5th edition, Springer Heidelberg Germany, 2012, from the same authors). However, this analysis is not entirely appropriate. It assumes that time to first outpatient check is equal to time to relapse. However, instead of a time to relapse an interval is given, in which the relapse has occurred, and so this variable is somewhat more loose than the usual variable time to event. An appropriate statistic for the current variable would be the mean time to relapse inferenced from a generalized linear model with an interval censored link function, rather than the proportional hazard method of Cox.