Incidence of and predictive factors for lung cancer in patients with rheumatoid arthritis: A retrospective long-term follow-up study.

OBJECTIVES

The aim of this study was to determine the incidence and predictive factors of lung cancer in rheumatoid arthritis (RA).

METHODS

We conducted a retrospective follow-up study of patients who were diagnosed with RA at our institution between April 2001 and December 2022. Pulmonary complications were evaluated using high-resolution computed tomography (HRCT) at RA diagnosis. Patients were followed until the diagnosis of lung cancer, diagnosis of other malignancies, death, loss to follow-up, or the end of the study.

RESULTS

Among 771 RA patients, 3.5% were diagnosed with combined pulmonary fibrosis and emphysema (CPFE), 4.9% with interstitial lung disease (ILD) alone, and 6.0% with emphysema alone. During follow-up (mean of 9.3 years), the crude incidence rates of lung cancer per 1000 patient-years were 2.9 in all patients, 47.8 in CPFE patients, 10.5 in ILD patients, 11.9 in emphysema patients, and 0.8 in patients without these complications. Only male patients showed a higher incidence of lung cancer compared with the general population. In multivariable Fine-Gray regression analysis, the presence of HRCT-proven CPFE, ILD, and emphysema, and smoking history were identified as predictive factors for lung cancer in RA patients.

CONCLUSIONS

Close monitoring of lung cancer is needed for RA patients with smoking history and pulmonary complications, especially CPFE.