Elevated serum Cyfra 21-1 levels predict poor prognosis in thymic tumors: a retrospective single-center study

Currently, specific serum biomarkers for thymic tumors remain poorly characterized. This study aimed to investigate the diagnostic and prognostic value of potentially relevant serum tumor markers in this context.

Consecutive patients with thymic tumors treated at Shanghai Chest Hospital between November 2012 and December 2017 were retrospectively enrolled in this study. Serum levels of tumor markers, including carcinoembryonic antigen (CEA), cytokeratin 19 fragment (Cyfra 21-1), squamous cell carcinoma antigen (SCCA), neuron-specific enolase (NSE), and carbohydrate antigen 125 (CA125), were evaluated across clinical and pathological subgroups. Survival analyses were performed using Kaplan-Meier curves and Cox regression models.

A total of 301 consecutive patients were enrolled in the study, of whom 231 had thymomas, 58 had thymic carcinomas (TCs), and 12 had neuroendocrine tumors (NETs). None of the markers-CEA, SCCA, NSE, or CA125-showed significant associations with tumor characteristics or prognosis. Conversely, elevated Cyfra 21-1 levels were significantly associated with advanced tumor (T) stage [odds ratio (OR): 3.259, 95% confidence interval (CI): 1.250-8.496, P=0.02] and high-grade malignancies, including TCs and NETs (OR: 6.260, 95% CI: 2.491-15.736, P<0.001). After a median follow-up of 60 months, among the 222 patients who underwent upfront complete (R0) resection, elevated preoperative Cyfra 21-1 levels independently predicted worse freedom from recurrence [FFR; hazard ratio (HR): 7.590, 95% CI: 2.316-24.87, P=0.001).

Cyfra 21-1 demonstrates potential as a valuable serum biomarker for both the diagnosis and prognosis of thymic tumors. Particular attention should be directed toward the diagnosis, treatment strategy, and postoperative surveillance of patients presenting with elevated Cyfra 21-1 levels.