Rheumatoid arthritis was linked to increased risk of lung cancer: Study

A new study published in the journal of Arthritis & Rheumatology observed an almost 3-fold greater risk of lung cancer was related with rheumatoid arthritis (RA)-interstitial lung disease (ILD). The patients with RA have had decreased pain, impairment, or loss of function as conventional therapies have improved. However, comorbidities including cancer, infections, and cardiovascular disease remain a danger to RA patients, increasing their disease burden and shortening their life expectancy.

Pulmonary involvement is one of the most prevalent extra-articular symptoms of RA, with a prevalence rate of 5% to 30%, sometimes as high as 67%, in RA patients. In addition to being a prevalent pulmonary symptom in RA patients, interstitial lung disease is also linked to an increased risk of lung cancer. Thus, this study by Rebecca Brooks and colleagues assessed the risk of lung cancer in patients with rheumatoid arthritis and RA-interstitial lung disease.

Between 2000 and 2019, a matched cohort study of RA and RA-ILD was conducted retrospectively inside the Veterans Health Administration (VA). The validated administrative-based algorithms were used to identify RA and RA-ILD patients, who were subsequently matched (up to 1:10) with those without RA based on factors including age, gender, and VA membership year. The National Death Index and a VA oncology database were used to identify lung cancer cases. When evaluating the risk of lung cancer in matched people, conditional Cox regression models  were employed to account factors such as race, ethnicity, smoking status, exposure to Agent Orange, and comorbidity load. There were several sensitivity assessments carried out.

In this study, 72,795 RA and 633,937 non-RA participants were matched and there were 17,099 incident lung cancer cases over 4,481,323 patient-years. An elevated risk of lung cancer was shown to be independently correlated with RA in both incident and never-smoker populations. Prevalent RA-ILD (n=757) was observed to be more significantly linked with lung cancer risk than RA without ILD, when compared to non-RA controls. Similar results were obtained from analyses of both frequent and incident RA-ILD.

Overall, an estimated threefold greater risk was related with RA-ILD, where RA was linked to an elevated risk of lung cancer of over 50%. To reduce the burden caused by the primary cause of cancer-related mortality, increased surveillance for lung cancer in RA (particularly RA-ILD), may prove to be an effective tactic.

Reference:

Brooks, R. T., Luedders, B., Wheeler, A., Johnson, T. M., Yang, Y., Roul, P., Ganti, A. K., Singh, N., Sauer, B. C., Cannon, G. W., Baker, J. F., Mikuls, T. R., & England, B. R. (2024). The Risk of Lung Cancer in Rheumatoid Arthritis and Rheumatoid Arthritis‐Associated Interstitial Lung Disease. In Arthritis & Rheumatology. Wiley. https://doi.org/10.1002/art.42961