PD-L1 and survival in oral cavity squamous cell carcinoma

Abstract

Relevance. Prognostic value of PD-L1 expression in oral cavity squamous cell carcinoma (OCSCC) and its effect on survival is still controversial. It should be to determine the prognostic role of PD-L1 expression on tumor and immune cells of OCSCC and assess their effect on overall survival (OS) and progression-free survival (PFS).Materials and methods. A prospective study included 145 patients, first diagnosed with OCSCC. PD-L1 expression on tumor and immune cells, infiltrating tumor and its microenvironment, was assessed in all tumor samples by IHC, CPS was calculated. Cut-off values were determined by ROC analysis for identification of PD-L1 expression effect on OS and PFS.Results. Most patients with oral mucosa squamous cell carcinoma showed positive expression of PD-L1 on tumor (77.2%) and immune cells (92.4%). The median PD-L1 expression on tumor cells was 13.5% [1.0-40.0], the median PD-L1 expression on immune cells was 5.0% [1.0-11.0], and the median CPS – 18.0 [3.0-7.8]. Univariate and multivariate analyses revealed a significant negative effect of PD-L1 expression on immune cells ≤ 7% on OS (HR 0.66; 95% CI 0.45-0.93; p = 0.0498); PD-L1 expression in tumor cells ≤ 15% (HR 0.65; 95% CI 0.43-0.98; p = 0.0416) and CPS ≤ 21 (HR 0.62; 95% CI 0.44-0.92; p = 0.0183) for PFS. PD-L1 expression in tumor cells ≤ 6% (HR 0.71; 95% CI 0.47-1.08; p = 0.1096) and CPS ≤ 7 (RR 0.67; 95% CI 0.44-1.01; p = 0.0575) had a confident tendency to negative impact on OS.Conclusion. Positive PD-L1 expression in tumor and immune cells as well as CPS are effective additional factors in the prognosis of the disease course, OS and PFS in patients with OCSCC.