Abstract 4289: C-reactive protein and risk of lung cancer: A pooled analysis of 20 prospective cohorts

Abstract

Abstract Background: Inflammation may have an important role in the etiology of lung cancer, and several studies have reported that C-reactive protein (CRP) is associated with risk of lung cancer. To clarify this association, we conducted a pooled analysis of CRP and lung cancer risk using data from 20 prospective cohort studies. Methods: Within the NCI Cohort Consortium, we designed a prospective nested case-control study. Controls were selected from appropriate risk sets and were matched to cases on smoking status, sex, and age at blood draw. This analysis included 5,299 case-control pairs nested within 20 cohorts. Rate ratios (RR) and their 95% confidence intervals associated with a doubling in concentration of CRP were estimated using conditional logistic regression models. Results: Overall, higher circulating CRP was associated with an increased risk of lung cancer (RR 1.05, 95% CI [1.03, 1.08]). This association varied strongly by smoking status (p-heterogeneity < 0.01), being similar for current (1.09 [1.05, 1.13]) and former smokers (1.09 [1.04, 1.14]), but not for never smokers (0.95 [0.91, 1.00]). The association was strongest for cancers diagnosed less than 2 years after blood draw (1.21 [1.13, 1.29], p-heterogeneity < 0.01), and weakened as time between blood draw and diagnosis increased. The association was similar across all histological subtypes, with the exception of adenocarcinoma for which we observed no association. Conclusions: CRP is associated with risk of lung cancer. The fact that the association is restricted to ever-smokers, and is most prominent for cancers diagnosed in the first 2 years of follow-up, strongly suggests that CRP is not a causal risk factor, but rather a distal marker of disease. Citation Format: David C. Muller, Allison M. Hodge, Gianluca Severi, Qiuyin Cai, Klaus Meyer, Kjell Grankvist, Arnulf Langhammer, Paul Brennan, Mattias Johansson, Lung Cancer Cohort Consortium (LC3). C-reactive protein and risk of lung cancer: A pooled analysis of 20 prospective cohorts. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4289.