Predictive value of PD-L1 expression in response to immune checkpoint inhibitors for gastric cancer treatment: a systematic review and meta-analysis.

ABSTRACT

BACKGROUND: Which patients may benefit more from immune checkpoint inhibitors (ICIs) is still an important question. The present study aimed to investigate the role of the PD-L1 molecule in predicting the effectiveness of PD-1/PD-L1 inhibitors in gastric cancer patients. METHOD: We searched PubMed, Scopus, Web of Science, and EMBASE databases as of 25 March 202225 March 2022. RESULTS: Ten articles were included. When we used the TPS method for PD-L1 expression, none of the patients in tumor proportion score (TPS)≥1% and TPS < 1% groups took advantage of ICI therapy in terms of OS and PFS. However, gastric cancer patients with combined-positive score (CPS)≥1, CPS ≥ 5, and CPS ≥ 10 tumors represented superior OS for ICIs over the control agents, while their counterparts (i.e. patients with CPS < 1, CPS < 5, and CPS < 10 tumors) did not. In the subgroup analysis when patients with CPS ≥ 1 were selected, Nivolumab improved the OS and PFS remarkably by 26% and 25% when compared with control agents, respectively. However, Pembrolizumab significantly increased the rate of disease progression by 47% relative to the control medications. CONCLUSION: Among patients suffering from gastric cancer, considering PD-L1 CPS thresholds seems to be a more reliable predictive factor than TPS threshold for lower rate of mortality when PD-1/PD-L1 inhibitors are administered.