Anaplastic thyroid cancer: multimodal treatment results

Anaplastic thyroid cancer is a rare and lethal disease. It accounts for 1-2% of thyroid malignancies, but specific mortality is higher than 90%. It is an aggressive locoregional disease with a high metastatic capacity. There is no agreement with regards to the best treatment. We analysed the results of treatment in a mestizo population treated in the National Cancer Institute (Mexico).

We reviewed 1,581 files of thyroid carcinomas; of these, 29 (1.83%) had anaplastic thyroid carcinoma. Demographic variables, clinical manifestations, tumour characteristics, and treatments were analysed.

The median age was 64.5 ± 13.2 years. Females were more affected (female/male ratio: 2.6:1); 21 cases occurred in women (72.4%), and eight in males (27.6%). The most common manifestations were neck enlargement (93.10%) and hoarseness (71.31%). The median tumour size was 8 cm (range: 4-20 cm). The percentage of cases which presented in clinical stage IVA was 10.3%, with 62.1% presenting in clinical stage IVb and 27.6% presenting in clinical stage VIc. Complete resection (R0) (p = 0.05), radiation doses of higher than 33.1 Gy (p = 0.04), and multimodal therapy were associated with better survival. Surgery plus radiotherapy with or without systemic treatment (p = 0.006). The median overall survival was 119 days (IC 95%, 36.3-201.6). Six-month, one-year and two-year survival was 37.9%, 21% and 13%, respectively.

Complete surgical resection is associated with better survival but is very difficult to achieve due to aggressive biological behaviour. Multimodal therapy is associated with better survival and a better quality of life. There is a need for more effective systemic treatments as extensive surgical resections have little overall benefit in highly invasive and metastatic disease.