OBJECTIVES: To assess the current management and resource use, and the associated costs from the perspective of the Belgian health care payer in patients with fluoropyrimidine, irinotecan and oxaliplatin refractory advanced colorectal cancer. METHODS: Data on management and resource utilization were collected using a two round questionnaire send to a representative expert panel. Patients with ≥10% and those with 1-10 % EGFR expressing tumour cells were considered separately as the latter are theoretically excluded from reimbursement for cetuximab, the currently available EGFR directed agent in Belgium. In the second round, the average, 10 and 90 percentile values of the responses collected in the first round were sent to each expert who could revise his original answer, acknowledge the average value or provide a new estimate and rank his answers on a (un)certainty scale. Costs were obtained by multiplying the average resource use with the specific unit cost (official tariffs). Total costs included costs related to preventive measures, adverse events, treatment evaluation and symptom control per treatment cycle (4 or 6w). RESULTS: Ten different treatment options were defined by the experts. If EGRF-expressing of the tumour is ≥10%, Irinotecan-Cetuximab is the treatment of choice in 87% of patients and responsible for 98% of the total cost of €16,611 (95%CI:€13,271-€20,234). If EGFR-expression of the tumour is between 1 and 10%, 48% of patients are treated by BSC alone. BSC is responsible for 18% of the mean overall cost of €6465 per 3 months (95%CI:€4456-€8851) for a patient in this setting. 5FU-MitomycinC is the most used chemotherapy regimen in this setting (26.04%). CONCLUSIONS: The majority of irinotecan refractory colorectal cancer patients with a ≥10% EGFR expression are having further active treatment with irinotecan-cetuximab responsible for 98% of total costs. In the 1-10 % EGFR group BSC is the most used treatment option.