Presentation and outcomes of patients with undifferentiated thyroid carcinoma: a national perspective

Background

Undifferentiated thyroid cancer (UTC) accounts for only 1-2% of all thyroid cancers. UTC is one of the most aggressive solid tumors with high metastatic rates and mortality. The objectives of this study are to examine the characteristics of patients with UTC and their overall survival.

Methods

Retrospective analysis utilizing the National Cancer Database, 2004-2014 is performed. The study population included adults (≥18 years) patients with UTC or differentiated thyroid carcinoma (DTC), which served as a reference group.

Results

A total of 1,870 UTC and 209,707 DTC patients were identified. The median follow-up time of UTC patients was 3.9 months (interquartile range: 1.6-9.0 months). When compared to DTC patients, patients with UTC were more likely to be ≥45-year-old [OR: 48.62, 95% CI: (35.75, 66.14), P<0.001], male [OR: 2.02, 95% CI: (1.84, 2.22), P<0.001], and/or black [OR: 1.27, 95% CI: (1.08, 1.49), P=0.004]. UTC patients were more likely to have Medicaid/Medicare or no insurance and treated in low-volume hospitals (P<0.001). Overall survival in patients with UTC was lower in patients older than 65 years [OR: 1.63, 95% CI: (1.12, 2.38), P=0.011], with multiple comorbidities [OR: 1.65, 95% CI: (1.02, 2.67), P=0.040] and/or presented with metastatic disease [OR: 1.93, 95% CI: (1.71, 2.17), P<0.001]. Compared to thyroidectomy alone, patients without metastasis who received adjuvant radiotherapy and/or chemotherapy had a better overall survival (P<0.001 each). In patients with metastatic disease, any intervention or combination of interventions other than thyroidectomy alone improved survival (P<0.05).

Conclusions

Older age, male, and/or black are associated with a higher prevalence of UTC compared to DTC. Although overall survival is poor in UTC, utilization of multi-modal treatment may improve survival.

Primary squamous cell carcinoma of the thyroid: a case report

Primary squamous cell carcinoma of the thyroid (PSCCT) is a rare and rapidly progressive malignancy that carries a poor prognosis. PSCCT is easily misdiagnosed as acute thyroiditis or as another thyroid malignancy. We have reported a 76-year-old woman who presented with progressive neck pain for 1 month. Thyroid function tests revealed subclinical thyrotoxicosis. Ultrasound disclosed a solid nodule with calcification in the right thyroid lobe. Laboratory findings included neutrophilic leukocytosis and an elevated erythrocyte sedimentation rate. The patient's condition was diagnosed as subacute thyroiditis, and she was treated with cefixime and ibuprofen. However, her treatment response was poor. She was then treated with oral prednisone. Her neck pain gradually resolved. The patient subsequently developed dysphagia, choking, dyspnea, and dysphonia with an insidious onset. Further examinations including computed tomography and painless gastroscopy revealed that the volume of the thyroid gland had increased significantly, extending to the anterior superior mediastinum. The trachea and esophagus were stenotic because of external compression. Partial thyroidectomy and tracheotomy were performed under extracorporeal membrane oxygenation. The diagnosis of PSCCT was established via histopathology and immunohistochemistry.

Dissecting Anaplastic Thyroid Carcinoma: A Comprehensive Clinical, Histologic, Immunophenotypic, and Molecular Study of 360 Cases

Background: Anaplastic thyroid carcinoma (ATC) is nearly always fatal. Large studies on ATC are exceedingly rare. We aimed to study the clinical, genotypic, and histologic characteristics of ATC in the largest retrospective cohort of ATC to date. Methods: Three hundred sixty patients with ATC from two tertiary centers were studied. Molecular testing was performed in 126 cases including 107 using next-generation sequencing. Results: The median patients' age was 68 years. Differentiated thyroid carcinoma (DTC) was present in 208 cases (58%), the most common being papillary carcinoma (n = 150). The 1-, 2-, 3-, and 5-year overall survival (OS) was 36%, 17%, 13%, and 11%, respectively. On univariate analysis, age, resectability, chemotherapy, radiotherapy, margin status, encapsulation, gross residual disease, gross extrathyroidal extension, percentage, and size of ATC in the primary tumor predicted OS (p < 0.05). Age, resectability, chemotherapy, and gross residual disease were independent prognostic factors in the entire cohort, while gross residual disease was the only independent predictor of OS in patients who had resection of their tumor. BRAF, RAS, TERT promoter, TP53, PIK3CA, E1F1AX, and PTEN mutations were detected in 45%, 24%, 75%, 63%, 18%, 14%, and 14% of ATC, respectively. Concomitant BRAF/RAS and TERT mutations were associated with worse outcome than mutation in only one of the genes. BRAF-mutated and RAS-mutated ATCs had similar frequency of nodal and distant metastasis. Twelve cases were pure squamous cell carcinoma, 60% of which carried BRAF^V600E mutation and showed a similar OS to other ATCs. Conclusions: (i) Gross residual disease remains the most crucial indicator of outcome in ATC. (ii) Encapsulation, margin status, percentage, and size of ATC in the primary were prognostically relevant. (iii) Pure thyroid squamous cell carcinoma may be considered as ATC given a BRAF^V600E genotype and similar outcome. (iv) In contrast to DTC, BRAF-mutated and RAS-mutated ATCs have similar metastatic spread. (v) Concomitant mutations of BRAF or RAS with TERT confer a worse prognosis.

Genetic alterations in poorly differentiated and undifferentiated thyroid carcinomas

Thyroid gland presents a wide spectrum of tumours derived from follicular cells that range from well differentiated, papillary and follicular carcinoma (PTC and FTC, respectively), usually carrying a good prognosis, to the clinically aggressive, poorly differentiated (PDTC) and undifferentiated thyroid carcinoma (UTC).It is usually accepted that PDTC and UTC occur either de novo or progress from a pre-existing well differentiated carcinoma through a multistep process of genetic and epigenetic changes that lead to clonal expansion and neoplastic development. Mutations and epigenetic alterations in PDTC and UTC are far from being totally clarified. Assuming that PDTC and UTC may derive from well differentiated thyroid carcinomas (WDTC), it is expected that some PDTC and UTC would harbour genetic alterations that are typical of PTC and FTC. This is the case for some molecular markers (BRAF and NRAS) that are present in WDTC, PDTC and UTC. Other genes, namely P53, are almost exclusively detected in less differentiated and undifferentiated thyroid tumours, supporting a diagnosis of PDTC or, much more often, UTC. Thyroid-specific rearrangements RET/PTC and PAX8/PPARγ, on the other hand, are rarely found in PDTC and UTC, suggesting that these genetic alterations do not predispose cells to dedifferentiation. In the present review we have summarized the molecular changes associated with the two most aggressive types of thyroid cancer.