Patient Preferences for Adjuvant Interferon Alfa-2b Treatment

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Abstract
PURPOSE: Although trials of adjuvant interferon alfa-2b (IFNα-2b) in high-risk melanoma patients suggest improvement in disease-free survival, it is unclear whether treatment offers improvement in overall survival. Widespread use of adjuvant IFNα-2b has been tempered by its significant toxicity. To quantify the trade-offs between IFNα-2b toxicity and survival, we assessed patient utilities for health states associated with IFN therapy. Utilities are measures of preference for a particular health state on a scale of 0 (death) to 1 (perfect health). PATIENTS AND METHODS: We assessed utilities for health states associated with adjuvant IFN among 107 low-risk melanoma patients using the standard gamble technique. Health states described four IFNα-2b toxicity scenarios and the following three posttreatment outcomes: disease-free health and melanoma recurrence (with or without IFNα-2b) leading to cancer death. We also asked patients the improvement in 5-year disease-free survival they would require to tolerate IFN. RESULTS: Utilities for melanoma recurrence with or without IFNα-2b were significantly lower than utilities for all IFNα-2b toxicities but were not significantly different from each other. At least half of the patients were willing to tolerate mild-moderate and severe IFNα-2b toxicity for 4% and 10% improvements, respectively, in 5-year disease-free survival. CONCLUSION: On average, patients rate quality of life with melanoma recurrence much lower than even severe IFNα-2b toxicity. These results suggest that recurrence-free survival is highly valued by patients. The utilities measured in our study can be applied directly to quality-of-life determinations in clinical trials of adjuvant IFNα-2b to measure the net benefit of therapy.