Elevated CRP associated with cancer risk in cancer-free people

High levels of C-reactive protein were associated with a 30% increased risk for developing any cancer and a greater increased risk for lung and possibly colorectal cancers, according to data from a prospective study.

The study included 10,408 people from Denmark’s general population whose CRP was measured at baseline. Participants were followed for 16 years; 1,624 developed cancer, of which 998 died during follow-up. Patients with a cancer diagnosis at baseline were excluded. Levels of CRP were defined by category, >3 mg/L vs. <1 mg/L, or quintiles.

According to the researchers, increasing levels of CRP by quintiles correlated with an increasing risk for incident cancer (P=.02); the same was true for CRP by categories (P=.06). The multifactorally adjusted HR for developing cancer with CRP levels >3 mg/L vs. <1 mg/L and highest vs. lowest CRP quintile was 1.3 (95% CI, 1.0-1.6).

Higher CRP levels were associated with an increased risk for lung cancer (HR=2.1). However, higher levels of CRP were not associated with a statistically significant increased risk for colorectal (HR=1.7) or breast cancers (HR=0.9).

In those patients who were diagnosed with cancer during follow-up, the HR for early death was 1.8 (95% CI, 1.2-2.7) for CRP >3 mg/L vs. <1 mg/L and 1.4 (95% CI, 1.1-1.7) for the highest vs. lowest quintile. Early death was associated with higher CRP levels among patients with localized disease, but not in those with metastases (P=.03). – by Stacey L. Adams

Allin KH. J Clin Oncol. 2009;doi:10.1200/JCO.2008.19.8440.

One must wonder whether smoking — with or without obvious pulmonary inflammatory disease — raises CRP levels and skews these results at least regarding lung cancer association.

– Harry S. Jacob, MD

HemOncToday Chief Medical Editor