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 a nalysis of treatment effect on tumour response and survival. It relies on t he definition of two transient states between which individuals may move ov er time, that is, response and non-response, and of one absorbing state, de ath. Three models are discussed according to the underlying Markov and dura tion dependence assumptions, as well as a marginal modelling of repeated tr ansitions between the two transient states. We illustrate the proposed meth ods with data from a randomized clinical trial assessing the effect of flud arabine in patients with advanced chronic lymphocytic leukaemia. Copyright (C) 2000 John Wiley & Sons, Ltd.