The Prognostic Value of Tumor Infiltrating Lymphocytes After Radical Cystectomy for Bladder Cancer: A Systematic Review and Meta-Analysis

Background: We aimed to assess the prognostic value of tumor infiltrating lymphocytes (TILs) in patients with bladder cancer (BC) after radical cystectomy (RC). Materials and Methods: We searched Pubmed, Web of Science and Scopus in April 2022 to identify studies assessing the prognostic value of TILs, including a subset of lymphocytes (eg, CD3, CD8, FOXP3), after RC. The endpoints were overall survival and recurrent free survival. Subgroup analyses were performed based on the evaluation method for TILs (ie, CD3, CD8, FOXP3, HE staining). Results: Overall, 9 studies comprising 1413 patients were included in this meta-analysis. The meta-analysis revealed that elevated expressions of TILs were significantly associated with favorable OS (pooled hazard ratio [HR]: 0.65, 95% confidence interval [CI]: 0.51-0.83) and RFS (pooled HR: 0.48, 95% CI: 0.35-0.64). In subgroup analyses, high CD8+ TILs were also associated with favorable OS (HR: 0.51, 95% CI: 0.33-0.80) and RFS (pooled HR: 0.53, 95% CI: 0.36-0.76). Among 3 studies comprising 146 patients, high intratumoral TILs were significantly associated with favorable OS (pooled HR: 0.34, 95% CI: 0.19-0.60). Conclusion: TILs are useful prognostic markers in patients treated with RC for BC. Although the prognostic value of TILs is varied, depending on the subset and infiltration site, CD8+ TILs and intratumoral TILs are associated with oncologic outcomes. Further studies are warranted to explicate the predictive value of TILs on the response to perioperative to clinical in with BC.