Transfusions Worsen Outcomes After Colorectal Cancer Surgery

The risks of death, postoperative infection, and other adverse clinical outcomes were significantly increased among patients undergoing colorectal cancer surgery who received perioperative allogeneic blood transfusions, according to a meta-analysis of 55 studies published in the August issue of Annals of Surgery.

Dr. Austin G. Acheson of the Nottingham (England) Digestive Disease Center at Queen’s Medical Centre and his associates reviewed 12 prospective studies and 43 retrospective cohort studies published between December 2004 and October 2010. The studies included 20,795 patients who were followed for a mean of about 5 years after undergoing surgery for colorectal cancer. Almost 60% (12,242) of these patients received a mean of three units of allogeneic red blood cells (Ann. Surg. 2012;256:235-44).

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Patients who were transfused tended to be older, and the transfusion rate was significantly higher in women, those undergoing rectal surgery (compared with those undergoing right or left colon surgery), those with greater surgical blood loss, and those with worsening Duke's stage.

All associations between ABT and the adverse clinical outcomes described below were statistically significant.

The rates of all-cause mortality in the 29 studies that looked at this outcome were 45% among the patients who received blood transfusions vs. 35% of those who did not, a significant difference that represented a 72% increased risk. After adjusting for the duration of the observation period, the investigators found that the annual incidence of all-cause mortality was almost 9% among the transfused patients vs. 6.5% among those who were not transfused.

The rate of cancer-related mortality was 31% vs. 24% in the 17 studies that measured this outcome, a 71% increased risk. After adjusting for the length of observation, the investigators said the annual incidence of cancer-related mortality was 5.4% of those transfused and 4% of those who were not.

The rate of the combined end point of death resulting from recurrence/metastasis was 43% of those who were transfused vs. 33% of those who were not transfused – a 66% increase in risk – in the 19 studies that measured this outcome.

The risk of postoperative infections in the 12 studies that measured this outcome was 29% among those who were transfused vs. 11% of those who were not transfused, which was more than a threefold increased risk. In the two studies that measured the need for surgical reintervention, the risk was increased fourfold among those who were transfused.

In the four studies that measured the length of hospitalization, the hospital stay was a mean of almost 18 days among those who received transfusions, compared with 14 days among those who did not.

Based on evidence in this meta-analysis and other studies showing that preoperative anemia is an independent risk factor for a worse prognosis after colon surgery, and based on the association between ABTs and poorer clinical outcomes in this meta-analysis, the authors wrote that "appropriate blood management measures should, therefore, be given an important place in the care of patients with CRC [colorectal cancer] undergoing elective surgery."

The use of ABT has dropped over the past 25 years because of improvements in patient care, and the authors stated that they believe efforts should be made to further minimize ABT use. Well-designed studies are needed "to determine whether and in which patients preoperative corrective measures of anemia, other than ABTs, will contribute not only in the field of colorectal surgery but also to improve clinical outcomes," they added.

The study was supported by an unrestricted research grant from Vifor Pharma AG, a specialty pharmaceuticals company focused on the treatment of iron deficiency, according to its website. The authors disclosed receiving honoraria and/or travel support for consulting or lecturing for companies that include Vifor, Ethicon Endosurgery, Johnson & Johnson, and AstraZeneca AG; their research departments received grant support from companies that included Vifor.