Modelling survival data with crossing hazards

We revisit the crossing hazards problem in survival analysis and compare the use of Cox's semi-parametric model with a parametric non-PH model from the generalised time-dependent logistic family(GTDL). A set of gastric can- cer data is analysed and a GTDL gamma-frailty model is shown to explain the observed data well. The role of heterogeneity in the crossing hazards problem is discussed.