Tumor size combined with staging systems for thymoma recurrence prediction: A 28-year experience

Background: We evaluated a new thymoma prognosis prediction model by combining current staging systems with tumor size. Methods: The clinical records of thymoma patients in a single center between January 1993 and December 2021 were collected, and data on tumor size and stage and recurrence-free survival (RFS) was obtained. The prediction model was designed by combining staging with tumor size. Results: During 28 years, 219 thymoma patients were enrolled. Twenty-seven patients had a median RFS of 8.2 years. Further, 153 patients were categorized into limited stage and 66 patients into advanced stage. The RFS was statistically different between these two groups (P = 0.022). The largest area under the curve (AUC) of receiver operating characteristic (ROC) was the dividing group as 5 cm (AUC: 0.804). Conclusions: Combining tumor staging and size improves thymoma recurrence prediction. Patients with advanced stage and tumor size >5 cm may show a poor prognosis.