Cost-utility of adjuvant high-dose interferon alpha therapy in stage III cutaneous melanoma in Quebec.

OBJECTIVE: To estimate the cost-utility of adjuvant high-dose interferon in high-risk melanoma patients in Quebec compared to a watchful waiting strategy.
METHOD: A Markov model was developed that replicates the findings of the pivotal E1684 trial. It was then used to extrapolate survival over a period of 35 years. Costs of medical resources used during the first year were derived through a detailed analysis of a sample (n = 13) of patients treated in a leading academic hospital. Follow-up costs were assessed through a medical decision algorithm. Utilities were derived from a population-based survey (n = 104) in different locations in Quebec using the time trade-off method.
RESULTS: The mean incremental cost per quality-adjusted life-year of adjuvant Interferon therapy is equal to 55,090 CAN dollars over a follow-up of 7 years but drops down to 14,003 CAN dollars when extrapolated over 35 years.
CONCLUSIONS: Estimates of the cost-effectiveness of high-dose interferon in melanoma patients show an acceptable cost-effectiveness ratio if long-term survival is taken into account. Estimates are, however, strongly influenced by the observed trial differences in survival, the utility associated to health states, and the discount rate.