Diagnostic research in immune checkpoint inhibitor-related pneumonitis: a bibliometric analysis of research evolution, diagnostic focuses, and future priorities

Background: Immune checkpoint inhibitor-related pneumonitis (CIP) is an important pulmonary toxicity in cancer immunotherapy. Its diagnostic assessment is difficult because symptoms and imaging overlap with infection, radiation pneumonitis, tumor progression, pre-existing interstitial lung disease, and other drug-induced lung injuries. Although publications on CIP have increased in recent years, research on diagnostic assessment remains insufficiently described. Methods: Publications on CIP and diagnostic assessment were retrieved from the Web of Science Core Collection (WoSCC) and PubMed. After screening, 628 WoSCC records were included as the main dataset for bibliometric analysis, and 74 PubMed records were used for supplementary clinical-topic assessment. Microsoft Excel, VOSviewer, CiteSpace, Bibliometrix, and SCImago Graphica were used to examine publication trends, country and institutional contributions, author collaboration, journal distribution, keyword co-occurrence, clustering, burst terms, and PubMed-based diagnostic topic classification. Results: CIP research was sparse before 2015, increased after 2015, and accelerated after 2019, with the highest annual output observed in 2023. China published the highest number of papers, while the United States has the greatest citation impact. Institutional and author analysis identified active research groups mainly from China, the United States and Japan. Research is mainly published in oncology, immunology, thoracic medicine and respiratory journals. Keyword analysis shows a shift from melanoma, T cells and immune checkpoint inhibition towards clinically focused themes, including diagnosis, differential diagnosis, imaging features, bronchoalveolar lavage (BAL), biomarkers, risk factors and nomogram-based prediction. A supplementary PubMed analysis similarly highlights imaging features, BAL, bronchoscopy or pathological assessment, and risk prediction as the primary clinical diagnostic themes. Conclusion: Research into CIP has evolved from the recognition of immune-related pulmonary toxicity to diagnostic assessment, differential diagnosis and personalised risk assessment. Current diagnostic studies reflect the clinical challenge of distinguishing CIP from other pulmonary complications in patients receiving immunotherapy. Future research should focus on developing and validating standardised, multicenter diagnostic strategies linked to prognosis. Current research trends suggest that imaging findings, bronchoalveolar lavage fluid or histopathological assessment, biomarkers, baseline lung function, and predictive models may form key components of such strategies; however, their clinical utility requires validation through prospective studies.