The impact of preoperative anaemia and anaemic subtype on patient outcome in colorectal cancer

AIM: Preoperative anaemia is associated with adverse outcomes in colorectal cancer (CRC). To clarify the reason for this we aimed to comprehensively assess the association of preoperative anaemia with tumour characteristics, host systemic inflammation and nutrition status, and perioperative blood transfusion. METHOD: We used an integrated database of 592 CRC patients. The association of preoperative anaemic subtype, calculated from haemoglobin and erythrocyte mean corpuscular volume levels, with patient outcome, preoperative serum data relating to systemic inflammation and nutrition and perioperative blood transfusion was analysed. RESULTS: Preoperative anaemia was significantly associated with poorer overall survival and relapse-free survival (RFS); in particular microcytic anaemia had a trend to poorer RFS than other forms of anaemia (P = 0.0648). In addition, preoperative anaemia was significantly correlated with right-sided tumours, greater depth of tumour invasion, use of neoadjuvant chemotherapy, poorer prognostic nutritional index and higher modified Glasgow Prognostic Score (mGPS). Microcytic anaemia in particular had a strong association with a greater depth of tumour invasion (P = 0.0072) and higher mGPS (P = 0.0058) than other causes of anaemia. Perioperative blood transfusion for CRC patients with anaemia was associated with adverse outcomes. CONCLUSIONS: Preoperative anaemia, especially microcytic anaemia, was associated with poor patient outcomes, possibly due to poor systemic inflammatory and nutritional status, and it was not improved by perioperative blood transfusion. Our data suggest that preoperative anaemia and the anaemic subtype may serve as an easily available predictor of outcome in CRC.