Prognostic value of tertiary lymphoid structures in early clinical stage oral tongue squamous cell carcinoma

Background Tertiary lymphoid structures have been observed in several solid tumors and suggested to be a favorable prognostic factor. However, the prognostic value of tertiary lymphoid structures for early clinical stage (cT1/2N0) oral tongue squamous cell carcinoma (OTSCC) remains unclear. In this study, we aimed to evaluate the prognostic value of tertiary lymphoid structures in cT1/2N0 stage OTSCC. Methods Ninety-seven patients with cT1/2N0 stage OTSCC were enrolled in this study. Tertiary lymphoid structures were assessed in paraffin sections with H.E and immunohistochemistry staining. Overall and disease-free survivals were evaluated by the Kaplan-Meier method. Cox proportional hazards regression models were used to assess their prognostic value. Results Tertiary lymphoid structures can be readily identified in cT1/2N0 stage OTSCC, including early tertiary lymphoid structures, primary follicle-like tertiary lymphoid structures, and secondary follicle-like tertiary lymphoid structures. Its frequency in OTSCC was 76.3% in the cohort. The presence of tertiary lymphoid structures was associated with favorable overall survival (p = 0.0176) and disease-free survival (p = 0.0183) in early clinical stage OTSCC. Cox regression models showed that tertiary lymphoid structures can serve as an independent prognostic factor for overall survival (HR = 0.434, 95% CI = 0.212-0.886, p = 0.022) and disease-free survival (HR = 0.459, 95% CI = 0.235-0.897, p = 0.023) in early clinical stage OTSCC. The group of low maturity of TLS combined with pN positive had the lowest overall survival (p = 0.0094) and disease-free survival (p = 0.0028). Conclusions Tertiary lymphoid structures are frequently observed in OTSCC. It is associated with a favorable prognosis for patients with cT1/2N0 stage OTSCC and may be used to predict immunotherapy sensitivity.