Research progress on treatment of pleural effusion related to immune checkpoint inhibitors

Immunotherapy for cancer, as an emerging treatment modality, has made significant strides in recent years and has become a crucial therapeutic approach following surgery, radiotherapy, chemotherapy, and targeted therapy. In particular, the clinical utilization of immune checkpoint inhibitors (ICIs) has not only enhanced the survival rates of patients with refractory or recurrent tumors but has also significantly optimized the overall strategy for cancer treatment. However, as the population undergoing cancer immunotherapy continues to grow, this expansion not only yields clinical benefits but also precipitates a range of specific adverse reactions known as immune-related adverse events (irAEs). Pleural effusion is a common and severe complication in cancer patients, significantly affecting both their quality of life and treatment outcomes. Typically, tumor-related pleural effusion is often due to pleural metastasis, with malignant pleural effusion (MPE) characterized by rapid growth, being difficult to control, and tendency for recurrence. With the approval of new drugs and the expansion of indications for existing medications, the number of cancer patients receiving ICIs treatment is increasing, bringing ICIs-related pleural effusion into focus. While ICIs treatment-related pleural effusion is relatively rare in clinical practice, it is closely linked to treatment choices of patients and prognosis. Unlike MPE, the pathogenesis of ICIs treatment-related pleural effusion is more complex, not only involving non-specific immune activation leading to autoimmune inflammatory reactions but also potentially related to nodular pleural granulomatous reactions, eosinophilic chronic pleurisy, and tumor-infiltrating lymphocytes. In terms of diagnosis, ICIs treatment-related pleural effusion is typically diagnosed through exclusion, requiring the exclusion of other causes such as tumor progression, radiotherapy, and chemotherapy-induced pleural effusion, adding complexity and difficulty to the diagnostic process. Treatment for ICIs treatment-related pleural effusion often involves glucocorticoids, tocilizumab, or infliximab, aiming to alleviate symptoms and improve prognosis by suppressing excessive immune reactions. Preventing the occurrence of ICIs treatment-related pleural effusion is equally crucial, necessitating comprehensive patient assessment before ICIs administration and continuous monitoring during treatment to promptly detect and manage potential adverse reactions. Through this comprehensive management approach, the impact of ICIs treatment-related pleural effusion on patient quality of life and treatment outcomes can be minimized, optimizing overall treatment results. This review aimed to explore the pathogenesis, histological features, clinical manifestations, diagnostic methods and treatment strategies of ICIs treatment-related pleural effusion, and delve into the characteristics of ICIs treatment-related pleural effusion, in order to enhance understanding of this complication and provide a reference for clinical practice.