Chemoradiation in anaplastic thyroid carcinomas

Background: ATC represents 1-2% of all thyroid carcinomas. Median survival is poor (3-10 months). Our goal is to update recommendations for RT in the context of new irradiation techniques.

Materials and methods: A search of the French and English literature was performed with terms: thyroid carcinoma, anaplastic, chemoradiation, radiation therapy and surgery. Level-based evidence remains limited in the absence of prospective studies and the small size of retrospective series of this rare tumor.

Results: Surgery when possible should be as complete as possible but without mutilation given the 8-month median survival of ATC. It should be followed by systematic chemoradiation in ATC. Initiation of treatment is an emergency given fast tumor doubling time. The most promising results of chemoradiation to date have been shown in series of radiation therapy (+/- acceleration) combined with doxorubicin +/- taxanes or cisplatin. Adjuvant chemotherapy (doxorubicin, cisplatine and/or taxane-based) may also be recommended given the metastatic potential of ATC and warrants further investigations. Data on neoadjuvant chemotherapy are missing. Intensity modulated radiation therapy offers clear dosimetric advantages and has the potential to improve tumor and nodal (posterior neck, mediastinum) coverage, i.e., locoregional control while optimally sparing the spinal cord, larynx, parotids, trachea and esophagus. PET-CT and MRI may be used for RT planning.

Conclusion: Chemoradiation with debulking surgery whenever possible is the mainstay of treatment of anaplastic thyroid carcinomas (ATC). EBRT using IMRT has the potential to improve local control. Taxane-doxorubicin concomitant chemoradiotherapy is worth further investigation.