Kaplan-Meier survival estimates of the survival function for the patients with ECD treated with (n = 46) or without (n = 7) interferon-α and/or PEGylated interferon-α. Comparison of patients treated with and without interferon-α and/or PEGylated interferon-α shows a significant difference in survival between those 2 groups (log-rank test, P = .004). Hash marks indicate censored persons.