Anaemia, blood loss and colorectal cancer

Abstract: Introduction: Colorectal cancer (CRC) is the fourth most common cancer worldwide and strikes both sexes. The age-adjusted 5-year survival in Sweden was 60% in the early 21 st century. Approximately 50% of patients are anaemic at the time of diagnosis. Many patients need blood transfusion due to anaemia or surgical blood-loss. Blood transfusions administered to patients with CRC have been associated with an increase in the risk for cancer recurrence, independent of tumour stage. One long-term complication to abdominal surgery is small bowel obstruction (SBO) necessitating further surgery. Hypotheses: • Anaemia prior to surgery and perioperative red blood cell transfusion increase overall mortality and risk of recurrence in patients after curative resections for CRC. • Blood-loss in surgery for colon cancer impairs overall survival. • The amount of blood lost at index surgery for colon cancer increases the risk of future surgery for SBO due to adhesions. • Major blood loss during surgery for rectal cancer increases the risk for SBO due to adhesions or tumour recurrence and reduces overall survival. Materials and methods: All studies are retrospective cohort studies of prospectively collected data. All patients who had abdominal resection for CRC stage I-III at Karolinska University hospital from 2007 to 2010 were included in the study considering the effects of anaemia and blood transfusion. Information was retrieved from the Swedish Colorectal Cancer Registry and linked to information on transfusion and laboratory data on haemoglobin. Patient records were validated for recurrent disease. The studies on blood loss are based on all patients with CRC in the Uppsala-Örebro region 1997 to 2003. Data from the Swedish Rectal and Regional Colon Cancer Registries were linked to information on hospital admissions for SBO and abdominal pain. Patient charts for those undergoing surgery for diagnoses congruent with SBO were validated for cause of SBO. Statistics were calculated using non-parametric methods, logistic regression, and Cox Proportional Hazards regression analyses. Results: Anaemia prior to surgery for CRC increased the risk of overall mortality (HR 2.2; 95% CI: 1.4-3.3). The analyses also revealed a trend towards an association between preoperative anaemia and recurrence (HR 1.6; 95% CI: 0.99-2.6). No association between perioperative blood transfusion and risk of recurrence or overall mortality was found. Blood loss ≥ median (250 ml) impaired overall survival (HR 1.1; 95% CI: 1.0-1.2) after surgery for colon cancer. There was no association between blood loss and survival for the rectal cancer patients. A blood loss ≥ median for patients with colon cancer (250 ml) increased the risk of future surgery for SBO caused by tumour recurrence (HR 2.2; 95% CI: 1.1-4.3). The same was found for patients with rectal cancers who had blood loss ≥ median 800 ml (HR 10.5; 95% CI: 1.4-81.5). There was no increased risk for surgery for SBO caused by adhesions for colon or rectal cancer patients. Conclusions: Anaemia prior to surgery for CRC is a predictive factor for mortality and a trend was seen towards an association with recurrence. Additional effort should be given to study this topic. No association was established between a perioperative blood transfusion and future risk of recurrence or mortality. Blood loss at surgery for CRC should be kept to a minimum to decrease mortality in patients with colon cancer and reduce future risk for SBO due to tumour recurrence.