Study Characteristics
All the 14 records were retrospective studies. 6716 advanced cancer patients receiving ICIs treatment were included. Among the14 studies, 3 studies were conducted in USA(22-24), 7 studies were conducted in Europe(25-31),1 study was conducted in China(32), 3 studies were conducted worldwide(12, 33, 34). All the studies provided the relationship between PPIs exposure and OS, 9 of them offered the association between PPIs exposure and PFS. Table 1 summarized the basic information of the studies in this study. The NOS score evaluating quality of included studies were also presented in Table1.
Table 1 Study Characteristics in This Meta-analysis