Oncological resection, myasthenia gravis and staging as prognostic factors in thymic tumours: a Chilean case series

Background: Thymic epithelial tumours are rare and highly heterogeneous. Reports from the United States suggest an overall incidence of 0.15 per 100,000/year. In contrast, the incidence of these tumours in Latin America is largely unknown and reports are scarce, somewhat limited to case reports.

Methods: Herein, we report a series of 38 thymic tumours from a single institution, retrospectively incorporated into this study. Patient characteristics and outcomes including age, sex, stage, paraneoplastic syndromes, treatment regimens and the date of decease were obtained from medical records.

Results: Most cases in our series were females and young age (<50 years old) and early stage by Masaoka-Koga or the Moran staging systems. Also, a 34% of patients had myasthenia gravis (MG). Next, we analysed overall survival rates in our series and found that the quality of surgery (R0, R1 or R2), MG status and staging (Masaoka-Koga, Moran or TNM) were prognostic factors. Finally, we compared our data to larger thymic tumour series.

Conclusions: Overall, our study confirms complete surgical resection as the standard, most effective treatment for thymic epithelial tumours. Also, the Masaoka-Koga staging system remains as a reliable prognostic factor but also the Moran staging system should be considered for thymomas.