Surgical treatment and prognosis of thymic squamous cell carcinoma: a retrospective analysis of 105 cases.

BACKGROUND: Thymic squamous cell carcinomas are rare malignancies with limited information regarding results of surgery therapy. The objective of the current study was to evaluate their clinical and pathologic features and possible prognostic factors.

METHODS: From February 2003 to December 2010, 105 consecutive surgical patients were enrolled in this study with pathologic confirmed thymic squamous cell carcinoma in Shanghai Chest Hospital. Clinical and pathologic data were retrospectively reviewed. Survival analysis was performed using the Kaplan-Meier and log rank tests. Multivariate analysis was performed using the Cox regression model.

RESULTS: The squamous cell subtype made up 73.4% of the thymic carcinomas and 16.1% of total thymic tumors. Four patients (3.8%) presented with myasthenia gravis. The 5-year overall survival rate and the disease-free survival rate were 59.5% and 57.6%, respectively. On multivariate analysis, only the completeness of resection (hazard ratio 3.692; 95% confidence interval: 1.827 to 7.464; p=0.001) was found to have significant impact on overall survival. Completeness of resection (hazard ratio 2.361; 95% confidence interval: 1.226 to 4.547; p=0.010) and chemotherapy (hazard ratio 0.307; 95% confidence interval: 0.134 to 0.704; p=0.005) were associated with disease-free survival.

CONCLUSIONS: Complete resection not only predicts better overall survival but also extends disease-free interval after resection of thymic squamous cell carcinoma. Our results provide additional evidence supporting an alternative clinical stage specific for thymic carcinoma.