Abstract
OBJECTIVES: We aimed to assess whether serum cytokine/chemokine concentrations predict incident cancer in RA patients. METHODS: Data from cancer-free enrollees in the Veterans Affairs Rheumatoid Arthritis (VARA) Registry were linked to a national VA oncology database and the National Death Index (NDI) to identify incident cancers. Seventeen serum cytokines/chemokines were measured from enrollment serum and an overall weighted cytokine/chemokine score (CK score) was calculated. Associations of cytokines/chemokines with all-site, lung, and lymphoproliferative cancers were assessed in Cox regression models accounting for relevant covariates including age, sex, RA disease activity, and smoking. RESULTS: In 1216 patients, 146 incident cancers (42 lung and 23 lymphoproliferative cancers) occurred over 10,072 patient-years of follow-up with a median time of 4.6 years from enrollment (cytokine/chemokine measurement) to cancer incidence. In fully adjusted models, CK score was associated with a higher risk of all-site (aHR 1.32, 95% CI 1.01-1.71, p < 0.001), lung (aHR 1.81, 1.40-2.34, p = 0.001), and lung/lymphoproliferative (aHR 1.54 [1.35-1.75], p < 0.001) cancer. The highest quartile of CK score was associated with a higher risk of all-site (aHR 1.91, 0.96-3.81, p = 0.07; p-trend = 0.005), lung (aHR 8.18, 1.63-41.23, p = 0.01; p-trend < 0.001), and lung/lymphoproliferative (aHR 4.56 [1.84-11.31], p = 0.001; p-trend < 0.001) cancer. Thirteen of 17 individual analytes were associated with incident cancer risk. CONCLUSION: Elevated cytokine/chemokine concentrations are predictive of future cancer in RA patients, particularly lung and lymphoproliferative cancers. These results suggest that the measurement of circulating cytokines/chemokines could be informative in cancer risk stratification and could provide insight into future cancer prevention strategies in RA, and possibly individuals without RA.