Normocytic anaemia is associated with systemic inflammation and poorer survival in patients with colorectal cancer treated with curative intent

Abstract

Background: The present study aimed to characterise the prevalence and prognostic impact of normocytic anaemia in patients undergoing curative treatment for colorectal cancer. Methods: All individuals invited to the first round of bowel cancer screening, diagnosed with colorectal cancer and treated with curative intent from April 2009 to March 2011 in a single health board were included. The modified Glasgow prognostic score (mGPS) was used to quantify preoperative systemic inflammation. Patients were grouped as having microcytic anaemia (Hb < 130 mg/L males, < 120 mg/L females and MCV < 80 fL), normocytic anaemia (Hb < 130 mg/L males, < 120 mg/L females and MCV 80–100 fL), or neither. Results: Of 395,097 patients invited to screening during the study period, 872 were diagnosed with colorectal cancer. Seven hundred seventy-seven patients had FBC measured at diagnosis, of which 78 (10%) had microcytic anaemia, and 180 (23%) normocytic anaemia. On multivariate binary logistic regression, microcytic anaemia was associated with T stage (OR 1.92, 95% CI 1.26–2.91, p = 0.002) and mGPS (OR 1.57, 95% CI 1.10–2.24, p = 0.013), while normocytic anaemia was associated with colonic tumours (OR = 2.51, 95% CI 1.10–4.01, p = 0.025), T stage (OR 1.38, 95% CI 1.05–1.81, p = 0.022), and mGPS (OR 1.52, 95% CI 1.12–2.05, p = 0.007). On univariate Cox regression, there was no significant association between microcytic anaemia and cancer specific survival (CSS) (p = 0.969). Normocytic anaemia was significantly associated with poorer CSS (HR 1.55, 95% CI 1.13–2.12, p = 0.007). Conclusions: Normocytic anaemia was associated with systemic inflammation and poorer CSS. Inflammation may drive both anaemia and disease recurrence in these patients, and targeting this process may improve both.