Cutaneous adverse events in patients treated with PD-1/PD-L1 checkpoint inhibitors and their association with survival: a systematic review and meta-analysis

Immune-related cutaneous adverse events (irCAEs) in patients treated with programmed cell death-1/programmed death-ligand 1 (PD-1/PD-L1) checkpoint inhibitors may be associated with better clinical outcomes. However, the extent to which these results can be extrapolated to all tumour types remains unclear. Herein, we conducted a meta-analysis of patients with cancer receiving anti-PD-1/PD-L1 immunotherapy, to determine the cumulative incidence of irCAEs and their association with survival. We systematically searched six databases (PubMed, Embase, Cochrane, CNKI, CSPD, and CQVIP database) for all cohort studies reporting the relationship between irCAEs and patient survival from the time of database construction to 1 November, 2020. The primary outcomes were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS), with complete remission (CR), partial remission (PR), stable disease (SD), and progressive disease (PD) as secondary outcomes. Patients with irCAEs exhibited higher ORR, and were more likely to report CR and PR and less likely to develop PD than those who did not experience irCAEs. Moreover, the occurrence of irCAEs was significantly associated with both favourable PFS and OS. Therefore, patients with irCAEs have better survival benefit and a significantly lower risk of tumour progression or death. Hence, the occurrence of irCAEs may be a useful marker for predicting the clinical efficacy of anti-PD-1/PD-L1 immunotherapy.