Background: Treatment for patients with radioactive
iodine (RAI)-refractory differentiated
thyroid carcinoma (DTC) is challenging. Recently, two
tyrosine kinase inhibitors (
sorafenib and
lenvatinib) have been approved and showed benefits for progression-free survival with tolerable adverse events. Methods: This is an extension study of a previous multicenter, retrospective cohort study of real-world experience in treating 98 patients with progressive RAI-refractory DTC with
sorafenib. The primary endpoint was overall survival (OS). The efficacy of
lenvatinib as
salvage therapy after
disease progression on first-line
sorafenib was evaluated by comparing outcomes in 32 patients who were treated with
lenvatinib with 41 patients who were not and therefore served as a no
salvage treatment group. Results: The median OS of all 98 patients treated with
sorafenib was 41.5 months, and the median progression-free survival was 13.5 months. Patients without disease-related symptoms before
sorafenib treatment had better OS than those with symptoms (hazard ratio [HR] = 0.56 [95% confidence interval, CI 0.31-0.99], p = 0.048). Larger
tumor size was associated with a minimally increased risk of death (HR = 1.02 [CI 1.00-1.03], p = 0.049). Best
tumor response was not associated with OS (p = 0.490).
Lenvatinib salvage treatment significantly improved OS in patients receiving it compared with those who did not (HR = 0.28 [CI 0.15-0.53], p < 0.001). The median OS from the time of
disease progression after first-line
sorafenib treatment was 4.9 months in no
salvage treatment group, whereas it was not reached in the
lenvatinib salvage group. Conclusions: The absence of disease-related symptoms and smaller
tumor burden was associated with survival benefits of first-line
sorafenib treatment in patients with progressive RAI-refractory DTC.
Lenvatinib salvage therapy was effective in improving OS in patients with
disease progression after first-line
sorafenib.