Anaplastic thyroid cancer:Improved understanding of what remains a deadly disease

Anaplastic thyroid cancer (ATC) is a rare, undifferentiated form of thyroid cancer accounting for less that 2 % of thyroid cancers. Here we provide an overview of the contemporary understanding of ATC as well as discussing in detail any pertinent updates in the molecular understanding and treatment of this disease with reference to the 2021 American Thyroid Association (ATA) guidelines. A review of the literature regarding the understanding, management and prognosis of ATC was undertaken using both Pubmed and Cochrane databases along with local institutional experience. Studies published in the last 5 years were prioritised for inclusion. Between 80 and 90 % of patients will have disease that has spread beyond the thyroid gland at presentation. Despite the use of aggressive, multimodal, conventional treatment strategies encompassing surgery and chemoradiotherapy, the median overall survival has remained between 3 and 6 months. Our understanding has evolved regarding the key oncogenic mutations involved in the development of ATC. These include BRAF, RAS, PI3K, PTEN, TP53 and TERT mutations. There is growing evidence that novel targeted therapies against these mutations may improve outcomes in this disease which has led to FDA approval of dabrafenib/trametinib combined BRAF/Mek inhibition. The prognosis of ATC remains dismal. Recent development and approval of targeted therapies offers hope of improved oncologic outcomes with further data eagerly awaited surrounding the impact of these targeted therapies.