The assessment of tumour response after treatment is one of the most important challenges in Oncology and the picture is so often complicated by the effects of therapy itself. Clinical assessment is still by far the most important method of assessment at our disposal but there is increasing dependence on investigations of all types as indices of response. This depen dence may be misplaced if inappropriate investigations are pursued and we have tried to emphasise in this book the importance of selectivity. Some indices of assessment (e. g. tumour markers, organ imaging) have a vital role to...