Background: The tumor maximum area (TMA) of thymic epithelial tumors (TETs) is not mentioned in current staging systems. This study aimed to assess whether TMA is of prognostic significance in TETs.
Methods: Patients who underwent extended thymectomy for TETs from 2001 to 2019 at our institute were retrospectively reviewed. TMA was examined by computed tomography imaging prior to surgery. Time-dependent receiver operating characteristic (ROC) curves were used to divide the cohort into two groups. The relationships between the TMA and clinicopathological characteristics or survival outcomes were assessed. Cox proportional hazards models were used to identify independent prognostic factors.
Results: A total of 122 TET patients were included for evaluation, with a median age of 61 years (range 27-83). The time-dependent ROC curve indicated that the difference in 10-year overall survival (OS) was most significant for a TMA of 1392 mm2 (area under the curve 0.793); therefore, the two groups of larger (n = 40) and smaller (n = 82) TMAs were divided. The differences in adjuvant therapy, TNM stage, and disease progression between the two groups were significant (p < 0.05). Kaplan-Meier curves indicated that TET patients with a larger TMA had worse survival outcomes, including OS, progression-free survival (PFS) and disease-free survival (DFS) [p < 0.05]. TMA was demonstrated to be an independent prognostic factor of all of the above survival outcomes in multivariate analysis (p < 0.05).
Conclusions: A larger TMA is associated with a more advanced TNM stage and disease progression in TET patients and may indicate worse survival outcomes, even if more patients receive adjuvant therapy.