Introduction: We examined whether plasma C-reactive protein (CRP) levels at the time of diagnosis of breast cancer are associated with overall survival, disease-free survival, death from breast cancer, and recurrence of breast cancer.
Methods: We observed 2,910 women for up to seven years after they were diagnosed with invasive breast cancer (median follow-up time was three years). Plasma levels of high-sensitivity CRP were measured at the time of diagnosis and we assessed the association between CRP levels and risk of reduced overall and disease-free survival, death from breast cancer, and recurrence of breast cancer by using the Kaplan-Meier method and Cox proportional hazards regression. During follow-up, 383 women died (225 of whom died from breast cancer) and 118 women experienced recurrence of breast cancer.
Results: Elevated CRP levels across tertiles at the time of diagnosis were associated with reduced overall and disease-free survival and with increased risk of death from breast cancer (log-rank trend for all, P < 0.001), but not with recurrence. The multifactor-adjusted hazard ratios (HR) of reduced overall survival among women in the middle and highest versus the lowest tertile of CRP were 1.30 (95% CI, 0.97 to 1.73) and 1.94 (1.48 to 2.55), respectively. Corresponding HRs of reduced disease-free survival were 1.16 (0.89 to 1.50) and 1.76 (1.38 to 2.25) and of death from breast cancer 1.22 (0.84 to 1.78) and 1.66 (1.15 to 2.41). Dividing CRP levels into octiles resulted in a stepwise increased risk of reduced overall survival (P for trend <0.001) and the multifactor-adjusted HR among women in the highest versus the lowest octile of CRP was 2.51 (1.53 to 4.12). Compared to women with CRP levels in the 0 to 25% percentile (<0.78 mg/L), the multifactor-adjusted HR of reduced overall survival among women with CRP levels ≥95% percentile (≥16.4 mg/L) was 3.58 (2.36 to 5.42). Among women with HER2-positive tumours, the multifactor-adjusted HR of reduced overall survival for the highest versus the lowest tertile of CRP was 8.63 (2.04 to 36.4).
Conclusions: Elevated CRP levels at the time of diagnosis of breast cancer are associated with reduced overall and disease-free survival and with increased risk of death from breast cancer.