Relationship of platelet-to-lymphocyte ratio with tumor immune microenvironment and efficacy of anti-PD-1 combined with neoadjuvant chemotherapy in muscle invasive bladder cancer.

e14549 Background: The platelet-to-lymphocyte ratio (PLR) has been used to predict therapeutic response in different tumors. However, no assessments of its usefulness have been performed in muscle-invasive bladder cancer (MIBC) patients receiving anti-PD-1 combined with neoadjuvant chemotherapy. Methods: The respective data of 62 MIBC patients receiving anti-PD-1 combined with neoadjuvant chemotherapy were analyzed. Whether PLR might predict treatment response to anti-PD-1 plus neoadjuvant chemotherapy and the cutoff value of the parameter were determined by ROC curve analysis. Moreover, 31 tumor mRNA sequencing data before the treatment were collected and analyzed using ESTIMATE R package. Results: PLR before the second period (PLR2, cut-off = 122.38, AUC = 0.667, 95% CI: 0.529-0.805, sensitivity = 0.935, specificity = 0.452) seemed to be useful predictors to determine patients who have a response or no response. The PLR2-low and PLR2-high groups were divided according to median score (154.9), and the estimate score and the immune score were significantly higher in the PLR2-low group. Conclusions: The PLR2 allowed for the accurate and efficient stratification of MIBC patients receiving anti-PD-1 plus chemotherapy and is easily applicable for clinical practice at no additional cost. Meanwhile, we identified that the diagnostic performance of PLR2 might reflect the tumor immune microenvironment, which plays an important role in immune therapy.