Inflammation has been linked to
cancer but its role in
breast cancer is unclear. We investigated common
serum markers of
inflammation:
C-reactive protein (CRP),
albumin,
haptoglobin and white blood cells (WBC) in relation to
breast cancer incidence, severity and survival. A total of 155179 women aged 20 and older without any history of
cancer were selected from a large Swedish cohort. Hazard ratios (HRs) for
breast cancer were estimated with Cox regression, adjusting for potential confounders. Ordered and binomial logistic regression models were used to assess the associations of serum inflammatory markers with
breast cancer severity and oestrogen receptor (ER) positivity at diagnosis, on the other. Cumulative incidence functions by levels of inflammatory markers were assessed for early death from
breast cancer and all causes. During a mean follow-up of 18.3 years, 6606 women were diagnosed with
breast cancer, of whom 1474 died. A positive association with incident
breast cancer was seen for
haptoglobin ≥ 1.4g/l [HR 1.09; 95% confidence interval (CI): 1.00-1.18] compared to lower levels. No association was observed between inflammatory markers and
breast cancer severity or ER positivity. Higher
haptoglobin was linked to risk of early death from
breast cancer (HR: 1.27, 95% CI: 1.02-1.59), whereas higher risk of early death from all causes was additionally found with CRP ≥ 10mg/l (HR: 1.19, 95% CI: 1.04-1.36) and WBC ≥ 10×10(9)/l (HR: 1.57, 1.14-2.16). Our findings indicate that prediagnostic serum inflammatory markers were weakly linked to incident
breast cancer but corresponded to worse survival after diagnosis.