Surgical treatment of thymoma: an 11-year experience with 761 patients

Abstract

Objectives: Thymomas are rare, and information regarding their surgical outcomes and possible prognostic factors is limited. In this study, we aimed to determine the clinicopathological characteristics of thymoma and estimate independent predictors of both overall and disease-free survival in thymoma patients.

Methods: We carried out a retrospective review of the clinicopathological characteristics and prognostic factors in 761 consecutive patients with pathologically confirmed thymoma treated in Shanghai Chest Hospital between January 2001 and December 2011. Survival was calculated using the Kaplan-Meier method and evaluated with log-rank tests. Multivariable analysis was performed using the Cox regression model.

Results: Complete follow-up information was available for 544 patients. The overall survival rate was 92.8% at 5 years and 90.5% at 10 years. The 5- and 10-year disease-free survival was 87.9 and 82.1%, respectively. On multiple Cox regression analysis, the Masaoka-Koga clinical stage [odds ratio (OR), 2.057; 95% confidence interval (CI), 1.454-2.911; P < 0.01] and sex (OR, 2.244; 95% CI, 1.115-4.519; P = 0.02) were found to be independent predictors of overall survival. The Masaoka-Koga clinical stage (OR, 2.127; 95% CI, 1.487-3.042; P < 0.01) and completeness of resection (OR, 2.935; 95% CI, 1.410-6.109; P < 0.01) predicted disease-free survival.

Conclusions: The four-tiered Masaoka-Koga clinical stage is the most important prognostic factor, predicting not only overall survival but also disease-free survival after thymoma resection. Completeness of resection predicts disease-free survival, and the World Health Organization histological classification may not have significant prognostic implications.

Keywords: Classification; Prognosis; Staging; Surgical resection; Thymoma.