Diagnostic and prognostic relevance of inflammatory markers in surgically treated thymic epithelial tumors: An international multicenter study

Background

Complementary prognostic markers are needed in thymic epithelial tumors (TETs) to aid patient stratification and determine the most appropriate follow-up strategies. This study aimed to assess the diagnostic and prognostic relevance of blood-based inflammatory markers in a large cohort of surgically treated TET patients.

Material and Methods

A total of 743 TET patients who underwent surgical resection between 1999–2021 were included in this multicenter study. Inflammatory markers were recorded from the most recent preoperative blood cell count prior to surgery. Measured variables were rescaled and harmonized to obtain comparable values across the participating centers.

Results

Preoperative CRP was significantly higher in TET patients with increased tumor size (vs. those with T1 tumors, p = 0.035). Likewise, neutrophil-to-lymphocyte ratio (NLR) (p = 0.002) and platelet-to-lymphocyte ratio (PLR) (p < 0.001) were both significantly higher in thymic carcinomas than in thymomas. Notably, increased NLR and PLR were mainly attributed to significantly decreased lymphocyte levels in thymic carcinoma patients. Concerning survival outcomes, we found that elevated PLR and fibrinogen influenced overall survival (OS) (p = 0.002 and p = 0.018, respectively) and cause-specific survival (CSS) (p = 0.002 and p = 0.009, respectively) independently of other variables in our multivariate models, and they constituted negative prognosticators in TETs. Elevated CRP had an independent negative impact only on OS. Although elevated NLR was linked with impaired prognosis in our univariate model (p = 0.008), its independent prognostic significance could not be validated.

Conclusions

Using the so-far largest cohort of surgically treated TET patients, our study demonstrates that CRP, PLR, and NLR have diagnostic significance in TETs, while elevated PLR and fibrinogen constitute independent negative prognosticators for OS and CSS. Accordingly, the current multicenter study offers additional guidance in developing personalized surveillance protocols in thymoma and thymic carcinoma.