| Abstract: | The complication in analysing tumour data is that the tumours detected in a screening programme tend to be slowly progressive, which is the so-called left-truncated sampling that is inherent in screening studies. Under the assumption that all subjects have the same tumour growth function, Ghosh Proportional hazards regression for cancer studies, Biometrics 64 (2008), pp. 141–148] developed estimation procedures for proportional hazards model. In this note, by modelling growth function as a function of covariates and parameterizing the distribution function of left truncation time, we demonstrate that Ghosh's approach can be extended to the case when each subject has a specific growth function. A simulation study is conducted to demonstrate the potential usefulness of the proposed estimators for the regression parameters in the proportional hazards model. |
