Thymic Squamous Cell Carcinoma: A Population-Based Surveillance, Epidemiology, and End Result Analysis

Xudong Yang; Kejia Zhao; Chuan Li; Yanbo Yang; Chenglin Guo; Yi Pu; Lunxu Liu

doi:10.3389/fonc.2020.592023

Thymic Squamous Cell Carcinoma: A Population-Based Surveillance, Epidemiology, and End Result Analysis

Front Oncol. 2020 Dec 22:10:592023. doi: 10.3389/fonc.2020.592023. eCollection 2020.

Authors

Xudong Yang^{1

2}, Kejia Zhao^{1

2}, Chuan Li^{1

2}, Yanbo Yang^{1

2}, Chenglin Guo^{1

2}, Yi Pu^{1

2}, Lunxu Liu^{1

2}

Affiliations

¹ Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China.
² Western China Collaborative Innovation Center for Early Diagnosis and Multidisciplinary Therapy of Lung Cancer, Sichuan University, Chengdu, China.

Abstract

Objectives: Thymic squamous cell carcinoma (TSCC) is a rare neoplasm that has been sparsely cited in the literature. The aim of this study was to determine disease characteristics and prognostic factors of patients in a Surveillance, Epidemiology, and End Results (SEER) analysis.

Methods: Cases from 1990-2016 were retrieved from the SEER database and demographics, treatments, and survival outcomes were analyzed.

Results: The TSCC accounted for 72.4% of the thymic carcinomas and 7.2% of thymic tumors. The 276 patients (165 men) selected for analysis had a median age of 65 (24-85) years, and 201 patients were diagnosed with Masaoka-Koga stage III/IV. The median survival of TSCC was 59 months with a 49.0% 5-year OS rate, a better prognosis than lymphoepithelioma-like carcinoma (32.1%) and undifferentiated carcinoma (33.3%). Multivariate analysis revealed the Masaoka-Koga stage (p = 0.003) and surgical types (complete resection, incomplete resection, and none; p < 0.001) were determinants of survival. Complete resection had the best prognosis with a 72.7% 5-year OS rate. Chemotherapy was an independent protective factor (HR = 0.555, 95% CI 0.347-0.886; p = 0.014) though poor survival was showed in univariate analysis. And the survival benefit of chemotherapy was validated in PSM analysis (3-year OS rate was 77.7% with chemotherapy vs. 52.8% without chemotherapy; p = 0.014).

Conclusions: TSCC was frequently diagnosed in older patients with advanced Masaoka-Koga stage and had more favorable survival than other subtypes of thymic carcinomas. Complete resection is the preferred treatment. Masaoka-Koga stage and chemotherapy had a strong association with prognosis.

Keywords: SEER database; complete resection; prognosis; thymic carcinomas; thymic squamous cell carcinoma.