Prognostic value of tumor-infiltrating lymphocytes for patients with head and neck squamous cell carcinoma:Beyond the Abstract

Tumor-infiltrating lymphocytes (TILs) have been used to predict the prognosis of solid tumors for many years, as these cells serve as a readout of the interaction between the immune system and cancer cells.

There is emerging evidence to support the positive role of TILs in head and neck squamous cell carcinoma (HNSCC), but there are remain some controversial issues, and no standard process has been established for the evaluation of TILs. Specifically, the literature on TILs provides limited evidence of their prognostic role, and many findings have been based on small sample sizes. Moreover, the different evaluation criteria used make the results of different studies incomparable. 

Due to these issues, an acceptable method to assess the level of TILs in HNSCC is urgently needed. In this study, we established a standardized procedure for measuring the TIL level in HNSCC in the first place and confirmed the prognostic role of TIL levels (Figure 1). We used hematoxylin and eosin (H&E) staining to observe and assess the infiltration of lymphocytes in the tumor stromal area and then analyze the relationship between TIL level and recurrence or survival rate. The results showed that low TIL level was closely associated with need for radiotherapy and many adverse prognostic factors including advanced T stage, smoking history, alcohol history, and microscopic extracapsular spread. The TIL level are closely related to the prognosis of patients with HNSCC. A threshold value of 70% is appropriate for TIL assessment, as patients with a TIL level higher than 70% show a better prognosis. The Cox regression model showed that the TIL level was an independent prognostic factor for disease-free survival. More importantly, the results showed that our methods were a feasible approach and criterion to evaluate TILs. 

TILs are a promised biomarker and will be widely used in future clinical and research trial. We recommend our method to future studies about TILs in HNSCC and hope to reveal more information in pathological diagnosis, treatment choice and prognostic adjudication about TILs in HNSCC by our established evaluation criteria.

Figure 1 Standardized approach of TIL evaluation for HNSCC patients.

Written by: Zhien Feng, Qiaoshi Xu, Zhengxue Han. Department of Oral and Maxillofacial-Head and Neck Oncology, Beijing Stomatological Hospital, Capital Medical University, Beijing 100050, China.

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