Purpose: This study aimed at investigating the value of applying positron emission tomography (PET) to early predict the effect of immune checkpoint inhibitors (ICIs) in malignant tumors.
Methods: Electronic databases MEDLINE/PubMed, EMBASE, and Cochrane Library were searched to identify relevant trials. The primary endpoints were progression-free survival (PFS) and overall survival (OS). The results were analyzed utilizing Stata 12.0 statistical software. Subgroup analyses were implemented based on primary tumors, study designs, continents, type of ICIs, evaluation index of PET, and evaluated PET timing.
Results: Fifteen studies incorporating 664 individuals were eligible. Compared with PET nonresponse group, PET response group displayed a significantly prolonged PFS (HR 0.27, 95% CI [0.16, 0.44]; P < 0.001) and OS (HR 0.56, 95% CI [0.48, 0.65]; P < 0.001). Analogical outcomes were obtained in subgroup analyses of PFS in non-small cell lung cancer, prospective, America, ipilimumab, nivolumab/pembrolizumab combined ipilimumab, PET Response Criteria in Solid Tumors (PERCIST), baseline PET and early PET timing arms without heterogeneity; so did OS in melanoma, retrospective, Europe, America, ipilimumab, nivolumab/pembrolizumab, PERCIST, baseline metabolic tissue volume, baseline standard uptake value, and baseline total lesion glycolysis, baseline PET timing, early PET timing and late PET timing arms.
Conclusion: Our study demonstrated that PET was a promising approach to early predict the prognosis of ICIs for malignancies.
Keywords: ICIs; Immune checkpoint inhibitors; Malignant tumor; PET; Positron emission tomography.