Long-Term Outcomes of Surgery for Thymic Epithelial Tumors With Pleural Metastases

Thymic epithelial tumors (TETs) are broadly classified into thymomas and thymic carcinomas (TC). These can present with pleural dissemination at diagnosis (TNM stage IVA) or as recurrence. As the benefit of resection or re-resection for stage IVA disease is unclear, we sought to identify factors affecting clinical outcomes.

This single-institution case series includes patients with TET having pleural dissemination who underwent surgery between 2006 and 2022 for initial (S4) or recurrent (R4) stage IVA disease. The association between potential prognostic factors and survival was evaluated using Kaplan-Meier and Cox proportional hazard analyses.

A total of 71 patients underwent surgery for pleural metastases (median age 45 y, TC = 22, S4 = 44), with 43 (61%) receiving induction chemotherapy. Overall survival (OS) for S4 and R4 was 10.6 years and 5.7 years, respectively (p = 0.064). S4 patients with TC had a shorter median survival compared with thymomas (5.2 y versus 12.8 y; p value <0.0001). Lymph nodes (LN) were resected in 54 (76%) patients and were more often involved in TC (25% versus 11%). Stratifying by LN status at initial surgery revealed a potential difference in recurrence-free survival (RFS) outcome only for thymomas (p value = 0.053). R-status at initial resection did not impact OS, but median RFS was longer in patients with R4 thymomas after an R0 resection (3 y versus 1.0 y, p value = 0.0339).

Surgical resection of stage IVA TETs is associated with greater survival benefit for thymomas compared with TC. Further studies should focus on associations between LN status and both OS and RFS, along with predictive biomarkers.