[Primary squamous cell carcinoma of the thyroid: retrospective analysis of 28 cases].

Objective: To investigate the clinicopathological features, treatment outcomes and prognosis of patients with squamous cell carcinoma of the thyroid (SCCT).

Methods: Retrospective review of SCCT cases in our hospital from January 1999 to May 2012. Demographic data and clinical charts, including presenting symptoms, histologic grade of tumor, treatment, and outcome of 28 consecutive patients were obtained. Survival rates and prognostic factors were calculated with SPSS 13.0 software using the Kaplan-Meier method and multivariate Cox model survival analysis.

Results: SCCT accounted for only 0.36% of all types of thyroid malignancy. There were 15 males and 13 females, and the median age was 63 years. The presenting symptoms were neck masses (26/28) and hoarse voice (18/28). The 28 SCCTs included 15 high grade tumors, eight intermediate grade tumors and five low grade tumors. According to the UICC 2002 staging criteria, 16 patients were stage IVa, and 12 were stage IVb. Of the 28 patients, 19 underwent surgery plus postoperative radiotherapy, seven underwent surgery alone, and two received radiotherapy alone. The rates of lymph node metastasis and distant metastasis were 60.7% and 25.0%, respectively. The 1-year, 2-year and 5-year overall survival (OS) rate were 50.4%, 25.8% and 19.3%, respectively, and the median overall survival time was 12.2 months. Kaplan-Meier univariate survival analyses indicated that the sizes of the tumors, esophageal invasions and treatment policies are prognostic factors, and multivariate Cox model survival analyses confirmed that the sizes of the tumors and treatment policies were independent factors for OS. Multivariate survival analyses confirmed that the sizes of the tumors and treatment policies were independent factors for OS.

Conclusions: SCCT is a rare malignant tumor with strong invasive ability, high malignancy and poor prognosis. Combined modality therapy was strongly recommended, and surgical resection plus postoperative radiotherapy may be the main treatment protocol for patients with SCCT.