Anaplastic Transformation of Differentiated Thyroid Carcinoma

Abstract

Objectives Anaplastic thyroid carcinoma (ATC) is a rare but highly aggressive form of thyroid cancer. Increasingly, patients with ATC present with concurrent foci of well‐differentiated thyroid carcinoma (WDTC); however, the significance of these pathologic findings remains unclear. The objective of this study is to determine whether the presence of WDTC within anaplastic tumors is a prognosticator of survival. Methods A retrospective cohort study of all cases of biopsy‐proven ATC managed at a tertiary care academic medical center from 2002 to 2020 was performed. Mean age at diagnosis, median survival time, and locations of distant metastases were assessed. The impact of clinical markers such as presence of differentiation, demographic variables, and oncologic information on overall survival was also determined via univariate and multivariate analysis. Results Forty‐five patients were included in this study. The mean age at diagnosis was 69.1 years. Median survival time was 6.1 months after diagnosis. The most common location of distant metastases was the lung (40%). The presence of limited areas of WDTC in patients with predominantly anaplastic thyroid tumors was not significantly associated with improved outcomes (p = 0.509). Smaller tumor size and use of chemotherapy in ATC patients were significantly associated with prolonged survival (p = 0.026 and 0.010, respectively). Conclusions Clinical outcomes for ATC remain poor. The presence of foci of differentiation within anaplastic thyroid tumors does not appear to improve overall survival—the anaplastic component evidently drives outcomes. Further studies into novel therapies are needed to improve survival in ATC. Level of Evidence 4 Laryngoscope, 133:437–442, 2023

Association of Treatment Strategies and Tumor Characteristics With Overall Survival Among Patients With Anaplastic Thyroid Cancer

“…Han and colleagues reported that 10 (67%) of 15 patients with 24-month OS or longer had coexisting histologic findings showing differentiated thyroid carcinoma compared with 20 of 80 (25%) patients with less than 24-month OS. In contrast to these prior studies, Yu and colleagues reported that tumors with coexisting well-differentiated thyroid carcinoma did not have survival differences compared with ATC only (HR, 1.26; 95% CI, 0.64-2.47). The divergent conclusions reached in the report by Yu and colleagues may reflect the small sample size of 45 patients in that study.…”

Update on current diagnosis and management of anaplastic thyroid carcinoma

“…The 1-year disease specific survival was 53.3% for stage IVA, 36.5% for IVB and 13.1% for IVC[ 35 ]. A recent study from a tertiary academic hospital in the United States including 45 patients found a median survival of 6.1 mo; smaller tumors and chemotherapy were related to better survival[ 105 ]. It was found by regression analysis that age, distant metastases and tumor size were independent factors of worse prognosis[ 106 ].…”