The impact of BRAF targeting agents in advanced anaplastic thyroid cancer: a multi-institutional retrospective study in Taiwan.

Anaplastic thyroid cancer (ATC) is a rare but lethal thyroid cancer. Dabrafenib and trametinib has been the standard treatment for the patients with BRAF mutation based on phase II study. This study aimed to exam the impact of dabrafenib and trametinib in ATC patients. ATC patients treated in three institutes in Taiwan were retrospectively reviewed. The clinical features, BRAF status, and survivals were collected. Multivariate analysis was performed to determine the independent prognostic factors. A total of 44 ATC patients were enrolled in current study. Twelve (50%) out of 24 detected patients had BRAF V600E mutation and eleven received dabrafenib and trametinib treatment. Patients treated with dabrafenib and trametinib had longer overall survival (OS) than the patients without treatment with dabrafenib and trametinib (median OS: 10.4 months vs. 3.3 months, P=0.05). The objective response rate was 81.8% and progress-free survival was 7.4 months. Multivariate analysis identified prior surgery, treatment with dabrafenib and trametinib and metastasis to lung, brain, and bone were significant prognostic factors for OS. The benefit of prior surgery was significant in patients receiving dabrafenib and trametinib (P=0.017) rather than those without dabrafenib and trametinib (P=0.067). The current study provides the real-world evidence that targeted therapy with dabrafenib and trametinib was effective and significantly improved the OS for ATC patients. The role of prior surgery became important in the era of targeted therapy. Future studies should focus on resistance mechanisms and combination with immunotherapy for ATC patients.