Management of Anaplastic Thyroid Carcinoma: the Fruits from the ATC Research Consortium of Japan.

Anaplastic thyroid carcinoma (ATC) accounts for only 1 to 2% of all thyroid carcinomas, but it is one of the most lethal neoplasms in humans. To obtain further insights into this "orphan disease," we have established the ATC Research Consortium of Japan (ATCCJ) in 2009. It represents a multicenter registry for ATC that have been treated in Japan. To date, 67 institutions have taken part in the collaborative research system and over 1,200 cases have been accumulated in its database. Using this big data, several retrospective studies were carried out to evaluate 1) prognostic factors to determine initial treatment policy, 2) significance of extended radical surgery for Stage IVB cases, 3) characteristics of ATC incidentally found on pathological examination and 4) pathological features of ATC with long-term survival. Moreover, the ATCCJ has conducted an investigator-initiated, nationwide, prospective clinical trial since 2012; namely, the feasibility, safety and efficacy study of weekly paclitaxel administration for patients with ATC (UMIN: 000008574). Revised Japanese guidelines for treatment of thyroid tumors are going to adopt the recommendations from the results of this research. Since 2016, the ATCCJ has started the phase II study assessing the efficacy and safety of lenvatinib, a newly developed tyrosine kinase inhibitor for ATC (UMIN: 000020773). Our nationwide clinical trial network will strengthen the activity to recruit orphan disease patients and may discover new strategies to conquer this dismal malignancy in the near future.