Multimodal Treatments and Outcomes for Anaplastic Thyroid Cancer Before and After Tyrosine Kinase Inhibitor Therapy: A Real-World Experience.

BACKGROUND Anaplastic thyroid cancer (ATC) has dismal prognosis, and there is no effective treatment. We aimed to evaluate the efficacy of tyrosine kinase inhibitor (TKI) therapy in real world clinic, and to suggest the most effective treatment modality according to the combination of treatments. METHODS This retrospective study evaluated clinical outcomes and cause of death with multimodal treatments in patients with ATC at Samsung Medical Center. RESULTS A total of 120 patients received anti-cancer treatment for ATC. Seventy-seven (64.2%) patients underwent surgery, 64 (53.3%) received radiotherapy, 29 (24.2%) received cytotoxic chemotherapy, and 19 (15.8%) received TKI therapy. In the TKI therapy group, 8 achieved partial response (3 with lenvatinib and 5 with dabrafenib plus trametinib), and 2 patients with lenvatinib showed stable disease. Median progression-free survival (PFS) of the TKI therapy group was 2.7 months (range: 0.1-12.7) and their median overall survival (OS) was 12.4 months (range: 1.7-47.7). Patients who received surgery or radiotherapy for local control showed superior OS than those who did not. In a multivariate analysis, surgery, TKI therapy, younger age, and no distant metastasis were associated with favorable OS. The combination of surgery, radiotherapy, and TKI therapy (median OS: 34.3 months, 6-month survival rates: 77.8%) was the most effective. Compared to the era without TKI therapy, distant metastasis has recently become the major cause of death in ATC over airway problems. CONCLUSIONS Multimodality treatment including TKI therapy demonstrated prolonged survival with dabrafenib plus trametinib as the most effective therapeutic option demonstrated for BRAF mutant ATC patients.