Abstract
BACKGROUND: Although myasthenia gravis (MG) commonly coexists with thymoma, its prognostic role in thymoma recurrence is controversial. Therefore, we aimed to identify clinical and pathological predictors of recurrence after thymectomy in a single-center cohort. METHODS: We retrospectively reviewed adult patients who underwent thymectomy for pathologically confirmed thymoma between January 2000 and December 2023 at a single tertiary center. Patients with at least 12 months of follow-up were included. Clinical, surgical, and pathological features were compared between patients with and without MG. Survival outcomes, including recurrence-free survival (RFS, R0 subgroup), progression-free survival (PFS, overall cohort), and overall survival (OS), were analyzed using Kaplan-Meier methods with log-rank tests. Independent predictors of recurrence were evaluated using Cox proportional hazards regression restricted to patients with R0 resection. RESULTS: Patients with MG were significantly younger and more likely to undergo transsternal extended thymectomy than those without MG. Although thymoma recurrence was more frequent in the MG group, MG status was not significantly associated with RFS or OS. Kaplan-Meier analysis showed that advanced-stage thymoma (stage III-IV) was associated with significantly shorter RFS, PFS, and OS compared with early-stage disease. In multivariate Cox regression restricted to R0 resections, advanced Masaoka stage remained an independent predictor of recurrence, while tumor size showed only a borderline association. CONCLUSIONS: Advanced Masaoka stage is the strongest independent predictor of thymoma recurrence after complete resection. Tumor size demonstrated a borderline association, suggesting a potential contributory role that requires further validation. MG, although clinically important for peri- and post-operative management, was not independently associated with recurrence.