OBJECTIVE: This study aims to estimate the non chemotherapy costs of treatment of advanced metastatic colorectal cancer from the perspective of the UK National Health Service. METHODS: Resource use collected during comparative clinical trials often is insufficient in determining the actual costs of patient management. Large data bases can be used to estimate patient health care resource consumption, but these are not always available. Soliciting expert opinion from clinicians may provide the only reasonable data source. A questionnaire was developed to obtain resource utilization for routine treatment and monitoring, adverse event management and other clinical parameters in the first line setting. Responses were obtained from five oncologists from various centres in the UK with experience of treating advanced metastatic colorectal cancer with chemotherapy. Data on second line treatment came from resource use collected during a trial. RESULTS: The clinicians estimated that 40% of first line patients would receive only palliative care at disease progression and 60% would receive second line therapy. Resources included physicians, acute care admissions, labs, hospice, palliative drugs, community nurses and radiology. Non-Chemotherapy Costs