Tumor Infiltrating Lymphocytes and CD8+ T Cell Subsets as Prognostic Markers in Patients with Surgically Treated Laryngeal Squamous Cell Carcinoma.

To evaluate the prognostic significance of tumor infiltrating lymphocytes (TILs) and of CD8+ T-cell subsets in patients with surgically treated laryngeal squamous cell carcinoma (LSCC), LSCC from 283 patients were examined. TIL density was morphologically assessed on whole sections. CD8+ cell counts/mm2 were evaluated on multiple tissue microarray cores per tumor (median counts for high/low CD8+/mm2). TIL density and CD8+ counts weakly correlated with each other (Spearman's rho = 0.348). Heterogeneous CD8+ counts/mm2 were demonstrated in 28% of the tumors. In univariate analysis, a significant interaction was observed between CD8 expression and nodal status with respect to outcome; in node-positive patients, those with high CD8+ tumors had 77% lower risk of relapse (interaction p < 0.001) and 74% lower risk for death (interaction p = 0.002) compared to patients with low CD8+ tumors. In multivariate analysis, higher TIL density independently conferred lower risk for relapse in the entire cohort (HR 0.87; 95% CI 0.77-0.98; Wald's p = 0.017) and in node-positive patients (HR 0.41; 95% CI 0.23-0.75; p = 0.003) and, similarly, for death (p = 0.025 and p = 0.003, respectively). High CD8+ was not a significant independent prognostic marker in any analysis setting. The assessment of CD8+ infiltrates does not seem to offer additional prognostic information over the morphologically assessed TIL density. It also appears that the favorable prognostic impact of higher TIL density and CD8+ infiltrates mostly concerns node-positive but not node-negative disease. If validated in larger node-positive cohorts, these findings are worth considering for the diagnostic development of immune cell infiltrates in LSCC.