Background: The incidence of lung cancer (LC) is reported to be higher in patients with rheumatoid arthritis (RA). The present study investigated whether or not RA altered the clinical manifestation of LC.
Methods: In this retrospective, cohort study, a total of 23 patients with both RA and LC (RA + LC group), and 6,570 patients with primary LC alone (LCA group), were identified from records at Taipei Veterans General Hospital between 1993 and 2002. Data about clinical characteristics, smoking habit, tumor location, LC histology, staging, and survival, were compared between the 2 groups.
Results: There was no significant difference in mean age at LC diagnosis between the RA + LC and LCA groups (70.2 vs 67.6 years; p = 0.154). Adenocarcinoma was the major histologic type in both groups, especially among women. There was no significant difference in histology, location, or staging of LC between the RA + LC and LCA groups. In the RA + LC group, all patients had RA before LC was diagnosed; pulmonary fibrosis was noted in 3 patients, 1 of whom had secondary Sjogren's syndrome. Median survival in the LCA group was not significantly different from that in the RA + LC group (10 [95% confidence interval, CI, 9.6, 10.4] vs 11 [95% CI, 3.7, 18.3] months; p = 0.69); the relative risk of LCA compared with RA + LC for survival was 0.938 (95% CI, 0.555, 1.585). The incidence of LC in RA patients in our hospital was 1.32% (23 of 1,740 patients).
Conclusion: RA has no influence on LC stage and does not shorten the survival of LC patients.