Abstract
PurposeAnaplastic thyroid carcinoma (ATC) and primary squamous cell carcinoma of the thyroid (PSCCTh) have similar histological findings and are currently treated using the same approaches; however, the characteristics and prognosis of these cancers are poorly researched. The objective of this study was to determine the differences in characteristics between ATC and PSCCTh and establish prognostic models.Patients and MethodsAll variables of patients with ATC and PSCCTh, diagnosed from 2004–2015, were retrieved from the Surveillance, Epidemiology, and End Results Program (SEER) database. Percentage differences for categorical data were compared using the Chi-square test. Kaplan-Meier curves, log-rank test, and Cox-regression for survival analysis, and C-index value was used to evaluate the performance of the prognostic models.ResultsAfter application of the inclusion and exclusion criteria, a total of 1164 ATC and 124 PSCCTh patients, diagnosed from 2004 to 2015, were included in the study. There were no differences in sex, ethnicity, age, marital status, or percentage of proximal metastases between the two cancers; however, radiotherapy, chemotherapy, incidence of surgical treatment, and presence of multiple primary tumors were higher in patients with ATC than those with PSCCTh. Further cancer-specific survival (CSS) of patients with PSCCTh was better than that of patients with ATC. Prognostic factors were not identical for the two cancers. Multivariate Cox model analysis indicated that age, sex, radiotherapy, chemotherapy, surgery, multiple primary tumors, marital status, and distant metastasis status are independent prognostic factors for CSS in patients with ATC, while for patients with PSCCTh, the corresponding factors are age, radiotherapy, multiple primary tumors, and surgery. The C-index values of the two models were both > 0.8, indicating that the models exhibited good discriminative ability.ConclusionPrognostic factors influencing CSS were not identical in patients with ATC and PSCCTh. These findings indicate that different clinical treatment and management plans are required for patients with these two types of thyroid cancer.
Highlights
Anaplastic thyroid cancer (ATC) is the most aggressive type of primary thyroid cancer, and accounts for approximately 1%–2% of all thyroid tumors, most of which occur in elderly adults
Our results indicate that median cancer-specific survival (CSS) time was longer in patients with Primary squamous cell carcinoma of the thyroid (PSCCTh) than in those with ATC, consistent with previous studies [8]
In line with previous studies, we found that women comprise a higher proportion of patients with ATC and PSCCTh than men, which may be related to the biological properties of these cancers [10, 11]
Summary
Anaplastic thyroid cancer (ATC) is the most aggressive type of primary thyroid cancer, and accounts for approximately 1%–2% of all thyroid tumors, most of which occur in elderly adults. Primary squamous cell carcinoma of the thyroid (PSCCTh) is an extremely rare and highly aggressive malignant tumor, which comprises < 1% of all primary thyroid cancers and has poor prognosis. The most common symptom of PSCCTh is an enlarged anterior neck mass, followed by difficulty breathing or swallowing, and a change in voice. Both ATC and PSCCTh present with abundant squamous cell-like cells; the two conditions are easy to confuse during clinical diagnosis and are treated [5]
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