Measures of treatment effectiveness on tumour response and survival: a multi-state model approach.

This paper proposes the application of a counting process approach in the analysis of treatment effect on tumour response and survival. It relies on the definition of two transient states between which individuals may move over time, that is, response and non-response, and of one absorbing state, death. Three models are discussed according to the underlying Markov and duration dependence assumptions, as well as a marginal modelling of repeated transitions between the two transient states. We illustrate the proposed methods with data from a randomized clinical trial assessing the effect of fludarabine in patients with advanced chronic lymphocytic leukaemia. Copyright 2000 John Wiley & Sons, Ltd.