Prognostic Value of Tumour Infiltrating T-Lymphocytes (Tils) with Special Preference to CD8 Positive T-Lymphocyte in Muscle Invasive Urothelial Bladder Cancer

Background: Bladder cancer (BC) is one of the most prevalent malignant tumours in Egypt. Several studies reported talented results using combined tri-modality therapy in muscle invasive bladder cancer (MIBC) with transurethral resection, radiation therapy and platinum-based systemic chemotherapy. Tumour-infiltrating neutrophils (TINs) and lymphocytes (TILs) are major components of inflammatory cells in the tumour microenvironment. Objective: We analyzed intra tumoural CD8 T-lymphocyte and correlate the findings with the clinical response to assess patient response to chemoradiotherapy in relation to expression of CD8 TIL. Patients and Methods: This descriptive study included 80 patients with muscle invasive non-operable, non- metastatic bladder cancer who received chemoradiotherapy and had CD8 TIL testing by immunohistochemistry. Patients were followed up and then were divided according to the clinical response into complete clinical response (cCR) (39) and failure cCR groups (41). Results: There was statistically significant higher incidence in failure cCR group regarding hematological complications and hepatic toxicity. At cutoff value equal to 31, percent of CD8 infiltration had 74.36% sensitivity and 95.12% specificity in prediction of disease clinical response. Using univariate cox regression analysis, advanced age and high CD8% infiltration were associated with low incidence of failure cCR with statistically significant effect. While females, T3a stage, T4a stage and stage IIIa histopathological stage were associated with high incidence of failure cCR with statistically significant effect. Conclusion: CD8 infiltration was higher with statistically significant difference among cCR group (p < 0.001). Regarding percent of CD8, higher percent was associated with better survival (p < 0.001).