Impact of Neoadjuvant Chemotherapy on Concordance of PD-L1 Staining Fidelity between the Primary Tumor and Lymph Node Metastases in Bladder Cancer

Objective: To evaluate programmed death ligand 1 (PD-L1) staining fidelity between the primary tumor and associated lymph node metastases in bladder cancer. To secondarily evaluate whether neoadjuvant chemotherapy (NAC) affects this relationship.

Methods: Sixty-seven subjects with residual bladder cancer on cystectomy and associated positive lymph nodes were identified between 2008 and 2015. PD-L1 staining of tumor cells was evaluated using H score and 49 specimens were also evaluated using combined positive score (CPS). Univariable and multivariable logistic regression analysis were used to assess how various clinical variables affected odds of PD-L1 fidelity between primary and metastatic tumors.

Results: Tumor PD-L1 staining was concordant in 79.1% of cases and CPS was concordant in 79.6% of cases. NAC did not significantly impact odds of PD-L1 or CPS fidelity (OR 1.974, 95% CI 0.673-5.784, OR 0.500, 95% CI 0.093-2.700). Among clinical variables analyzed on univariable analysis of tumor PD-L1 fidelity, H-score, and PD-L1 staining intensity were associated with significantly increased odds of PD-L1 fidelity and the association with staining intensity was confirmed on multivariable analysis.

Conclusion: PD-L1 fidelity between primary bladder tumors and nodal metastases was observed in >75% of cases in this study. Additionally, NAC was not shown to diminish this propensity to maintain PD-L1 staining status. Further standardization of immunohistochemistry of tumor and infiltrating imsmune cells in metastatic bladder cancer is needed to improve application of therapeutics.