Background: The advent of PD-1/L1 inhibitors has changed the landscape for patients with non-small-cell lung cancer (NSCLC). Meanwhile, the adverse events of PD-1/L1 inhibitors have been focused. Methods: The Cochrane Central Register of Controlled Trials, PubMed and Embase databases and ClinicalTrials.gov were searched from inception to February 2021. Results: 18 studies involving 11,394 patients with NSCLC were included. PD-1/L1 inhibitor monotherapy was associated (relative risk, 95% confidence interval) with an increased risk of pericardial effusion (2.72 [1.45–5.12]; p = 0.002) and cardiac tamponade (2.76 [1.15–6.62]; p = 0.023), whereas PD-1/L1 inhibitors combined with chemotherapy did not increase the risk of pericardial effusion and cardiac tamponade (3.08 [0.93–10.21]; p = 0.066 and 3.27 [0.37–28.94]; p = 0.288, respectively). Conclusion: For patients with NSCLC, treatment with PD-1/L1 inhibitor monotherapy increases the risk of pericardial effusion and cardiac tamponade, but PD-1/L1 inhibitors combined with chemotherapy do not.

Background: Metastasis, a leading cause of cancer-related deaths, involves complex mechanisms. The premetastatic niche (PMN) is a crucial contributor to this process. Myeloid-derived suppressor cells (MDSCs) play an important role in PMN formation and promote tumor progression and metastasis. The Xiaoliu Pingyi recipe (XLPYR), a traditional Chinese medicine, is effective in preventing postoperative recurrence and metastasis in cancer patients. Objective: This study investigated the effects of XLPYR on MDSCs recruitment and on the expression of PMN markers and elucidated the mechanisms involved in the prevention of tumor metastasis. Methods: C57BL/6 mice were subcutaneously injected with Lewis cells and treated with cisplatin and XLPYR. Tumors were resected after 14 days after the establishment of a model of lung metastasis, and tumor volume and weight were measured. Lung metastases were observed 21 days after resection. MDSCs in the lung, spleen, and peripheral blood were detected by flow cytometry. Western blotting, qRT-PCR and ELISA were used to detect the expression of S100A8, S100A9, MMP9, LOX, and IL-6/STAT3 in premetastatic lung tissue. Results: XLPYR treatment inhibited tumor growth and prevented lung metastasis. Compared to mice without subcutaneous tumor cell transplantation, the model group had an increased proportion of MDSCs, higher expression of S100A8, S100A9, MMP9, and LOX in the premetastatic lung. XLPYR treatment reduced the proportion of MDSCs, S100A8, S100A9, MMP9, and LOX expression, and downregulated the IL-6/STAT3 pathway. Conclusions XLPYR may prevent MDSCs recruitment and reduce the expression of S100A8, MMP9, LOX, and IL6/STAT3 in premetastatic lung tissue, thus reducing lung metastases.