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

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 <130mg/L males, <120mg/L females and MCV <80fL), normocytic anaemia (Hb <130mg/L males, <120mg/L females and MCV 80-100fL), 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.