Nickan Research Institute Immunopathologia Persa 2423-8015 11 2 2025 07 01 Association between rheumatoid arthritis and lung neoplasm; a systematic review and meta-analysis e43792 e43792 10.34172/ipp.2025.43792 EN Amir Behnam Kharazmi https://orcid.org/0000-0003-1192-4893 Sajad Ataei Azimi https://orcid.org/0000-0003-4542-9647 Atefeh Nourmohammadi https://orcid.org/0009-0004-6887-8001 Sina Salati https://orcid.org/0000-0001-8817-3501 Gülüzar Özbolat https://orcid.org/0000-0002-3487-1088 Hamid Rastad https://orcid.org/0009-0003-9322-0394 Armin Attar https://orcid.org/0009-0006-0946-0259 Hossein Mardanparvar https://orcid.org/0000-0001-7455-5373 Seyed Amir Sheikholeslami https://orcid.org/0000-0002-0069-9785 Journal Article 10.34172/ipp.2025.43792 2024 11 14 2025 01 19 Introduction: Lung cancer is one of the most common malignancies in patients with rheumatoid arthritis (RA). Therefore, this study aimed to determine the association between RA and lung neoplasm using a systematic review and meta-analysis. Materials and Methods: This research was conducted according to the PRISMA guidelines. The databases ProQuest, PubMed, Embase, Web of Science, Cochrane, Scopus, and the search engine Google Scholar were searched up to October 8, 2024. Data analysis was performed using STATA 14 software, and P<0.05 was considered statistically significant. Results: A total of 24 cohort studies, comprising 792,699 participants, were evaluated. The results indicated that RA increased the risk of lung neoplasm. Specifically, the hazard ratio (HR) was 1.54 (95% CI: 1.33–1.77), the standardized incidence ratio (SIR) was 1.30 (95% CI: 1.19–1.41), and the risk ratio (RR) was 1.50 (95% CI: 1.31–1.71). RA increased the risk of lung neoplasm in both women (SIR: 1.24; 95% CI: 1.12, 1.39) and men (SIR: 1.71; 95% CI: 1.37, 2.15). No significant statistical association was found between RA and lung neoplasm in patients aged 30-39 years (SIR: 1.40; 95% CI: 0.64, 3.08) and 40-49 years (SIR: 0.64; 95% CI: 0.21, 1.93). However, in patients aged 50-59 years (SIR: 1.31; 95% CI: 1.18, 1.45) and 60-69 years (SIR: 1.63; 95% CI: 1.51, 1.77), RA increased the risk of lung neoplasm. Conclusion: Rheumatoid arthritis was associated with an increased risk of lung neoplasm, and this risk increased with age. The risk of lung neoplasm was higher in men than in women. Therefore, advanced age and male gender were identified as risk factors for lung neoplasm in RA patients. Registration: This study has been compiled based on the PRISMA checklist, and its protocol was registered on the PROSPERO (ID: CRD42024602266) and Research Registry (UIN: reviewregistry1900) websites.