Prognostic Significance of Combined PD-L1 Expression and Chemotherapeutic Status in Cholangiocarcinoma Patients

Background/Aim: Cholangiocarcinoma (CCA) is a malignant tumor with high mortality and recurrence rates after treatment. The discovery of prognostic markers is, therefore, essential for improving patient outcomes after treatment. This study aimed to investigate the prognostic value of membranous and cytoplasmic PD-L1 expression, individually and in combination. In addition, the combination of PD-L1 expression and chemotherapeutic status was also explored. Patients and Methods: The expression of PD-L1 was examined in 200 CCA patients using immunohistological staining, and its correlation with clinicopathological data was investigated using the Chi-squared test. Overall survival (OS) and recurrence-free survival (RFS) investigations were performed using Kaplan-Meier (log-rank) and Cox-regression analysis. Results: The results demonstrated that high PD-L1 expression in the membrane and low expression in the cytoplasm had a correlation with intrahepatic CCA and lymph node metastasis. Furthermore, these patients had shorter OS and RFS compared to other groups of patients. Moreover, when the expression of PD-L1 was combined with chemotherapeutic status, the result demonstrated that patients who had high expression of PD-L1 in the membrane with low expression of PD-L1 in the cytoplasm and did not receive adjuvant chemotherapy showed significantly shorter OS and RFS compared to other patients. This could be an independent prognostic factor for RFS and OS with HR 1.889 and 1.990, respectively. Conclusion: PD-L1 expression levels can serve as a valuable predictor of outcomes in CCA patients, especially when evaluated alongside chemotherapeutic status.