Tumor infiltrating lymphocytes in head and neck squamous cell carcinoma - Evaluation and clinical impact

Background: Head-and-neck squamous cell carcinomas (HNSCCs) are one of the most common malignancies worldwide. Emerging evidence reveals that tumor-infiltrating lymphocytes (TIL) provide valuable prognostic information in various malignancies, including HNSCC. Aims and Objectives: The present study aimed to evaluate a simple yet accurate method of counting TILs in HNSCCs. It was also done to determine if there is any correlation between different clinicopathological parameters of HNSCC and TIL counts. Materials and Methods: A retrospective institutional-based, observational study was undertaken for 1 year. Patients with histologically proven HNSCCs were included. All clinicopathological parameters were noted, and evaluation of TIL was meticulously done both in the stromal and intratumoral regions for each case. Standard statistical methods were employed for data analysis. Results: The present study included 81 patients, among which 51 (63%) were male and the rest (30, 37%) were female. The mean age of the patients was 55.3 +/- 10.5 years. Most tumors were located in the oral cavity (73, 90.1%). The most common histologic type was moderately differentiated (MD) squamous cell carcinoma (SCC) (50 cases, 61.7%). Stromal TIL score was high in 45 cases (55.6%). In 69 cases (85.2%), the intratumoral TIL level was low. A statistically significant correlation was found between TIL levels (both stromal and intratumoral TIL) and tumor differentiation, pT stage, and lymphovascular invasion. The correlation between intratumoral TIL level, age of patients, and pN stage was also statistically significant. Conclusion: TIL evaluation is an inexpensive, simple, and reproducible method, which furnishes relevant prognostic data. It has the potential for consideration of its inclusion in routine histopathological reports of HNSCCs.