Response to Targeted Therapy in BRAF Mutant Anaplastic Thyroid Cancer

Anaplastic thyroid cancer (ATC) is an aggressive uncommon malignancy with limited treatment. Traditional antineoplastic chemotherapy has not been successful in the management of metastatic ATC. As a result, the focus has shifted to the development of novel therapies for this disease. The availability of economical comprehensive genomic profiling (CGP) platforms with rapid turn-around to identify molecular aberrations in tumors that are potential therapeutic targets has increasingly changed the face of cancer therapy. Identification of targetable aberrations may help identify novel treatment options for ATC. Herein, we report our experience with a 47-year-old patient with metastatic ATC who experienced recurrent, progressive disease and rapid clinical deterioration despite surgery, radiation therapy, and treatment with 2 different chemotherapy regimens. She was found to have a BRAF V600E mutation on CGP, and was started on targeted therapy with the BRAF inhibitor dabrafenib and the MEK inhibitor trametinib. After 2 months of treatment, she showed a clinical and radiologic response. The patient remained on this combination for 9 months until evidence of disease progression. Discontinuation of these drugs was associated with rapid tumor growth. Through this case we want to emphasize the importance of early molecular sequencing and identification of genetic aberrations in patients with ATC, and using that information to develop therapies for ATC, an aggressive malignancy with limited therapy and a poor outcome.