RESUMEN
OBJECTIVE: 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 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 1,000 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. The standardized incidence ratios (95% confidence intervals [CI]) compared with the general population were 2.53 (1.29-3.77) for male patients and 0.89 (0.57-1.16) for female patients. In Fine-Gray regression analysis, adjusted hazard ratios (95% CI) of lung cancer were 13.48 (3.14-57.85) for CPFE, 6.42 (1.42-29.09) for ILD alone, and 4.65 (1.18-18.30) for emphysema alone versus without these complications, and 1.02 (1.01-1.04) per additional 1 pack-year for smoking history. These factors were not associated with the risk of other malignancies. CONCLUSION: Close monitoring of lung cancer is needed for RA patients with smoking history and pulmonary complications, especially CPFE.
RESUMEN
OBJECTIVE: Combined pulmonary fibrosis and emphysema (CPFE) is a syndrome characterized by the coexistence of emphysema and fibrotic interstitial lung disease (ILD). The aim of this study was to examine the effect of CPFE on lung cancer risk and lung cancer-related mortality in patients with rheumatoid arthritis (RA). METHODS: We conducted a multicenter retrospective cohort study of patients newly diagnosed with lung cancer at five community hospitals between June 2006 and December 2021. Patients were followed until lung cancer-related death, other-cause death, loss to follow-up, or the end of the study. We used the cumulative incidence function with Gray's test and Fine-Gray regression analysis for survival analysis. RESULTS: A total of 563 patients with biopsy-proven lung cancer were included (82 RA patients and 481 non-RA patients). The prevalence of CPFE was higher in RA patients than in non-RA patients (40.2% vs.10.0%) at lung cancer diagnosis. During follow-up, the crude incidence rate of lung cancer-related death was 0.29 and 0.10 per patient-year (PY) in RA and non-RA patients, and 0.32 and 0.07 per PY in patients with CPFE and patients without ILD or emphysema, respectively. The estimated death probability at 5 years differed between RA and non-RA patients (66% vs. 32%, p<0.001) and between patients with CPFE and patients without ILD or emphysema (71% vs. 24%, p<0.001). In addition to clinical cancer stage and no surgery within 1 month, RA and CPFE were identified as independent predictive factors for increased lung cancer-related mortality (RA: adjusted hazard ratio [HR], 2.49; 95% confidence interval [CI], 1.65-4.76; CPFE: adjusted HR 2.01; 95% CI 1.24-3.23). CONCLUSIONS: RA patients with lung cancer had a higher prevalence of CPFE and increased cancer-related mortality compared with non-RA patients. Close monitoring and optimal treatment strategies tailored to RA patients with CPFE are important to improve the poor prognosis of lung cancer.