 The cost analysis exists of two main parts. First, on the patient level, volumes of diagnostic and therapeutic care will be measured prospectively using standardized Case Report Forms CRF. In each participating hospital research nurses will register in the CRF the number of times a patient visits the out patient department, the number of days in hospital normal care and intensive care distinguished, the number and kind of diagnostic procedures CT, FDG-PET, ultrasonography, histological examination, the type and number of operations intra-operative ultrasonography, endoscopy, resection of liver metastases, the duration of the specific operations, the number and duration of therapeutic sessions, the amount and kind of pharmaceutical therapies e.g. pain killers, days in hospital normal care and intensive care distinguished and so on. This part of the CRF will be designed and pilot tested in the first months of the study. The second part of the cost analysis consists of determining the cost prices for each volume parameter to use these for multiplying the volumes registered for each participating patient. The Dutch guidelines for conducting pharmaco-economic studies CVZ, 1999 and the guidelines for cost analyses will be used Oostenbrink 2000. Because of the health care perspective of the study approximations of real integral costs will be used in the cost analysis. As a basis for the cost price calculations for each participating hospital a unique cost price, based on standardized calculation methods will be determined. For the baseline analysis a weighed average using the number of patients included in the study by each participating hospital will be used. Mean, median, range and standard deviation of the total medical costs per patient will be determined for each of the two patient groups. Skewness of the distribution will be examined to determine whether parametric or non-parametric statistical techniques will be used to test a possible statistical difference between the groups. Analysis will be performed on the basis of intention to treat. Besides this statistical analysis, the impact of deterministic variables, such as the cost prices used for the different volume parameters, will be investigated using sensitivity analyses on the basis of the range of extremes Briggs 1994. For definition of the range of extremes to be used in this sensitivity analysis, the range of the cost prices as calculated in the participating hospitals and the national guidelines will be used. 