Preoperative anemia, transfusions and survival in colorectal cancer surgery—A retrospective study

Perioperative anemia and blood transfusions are frequent and both are associated with a worse outcome in patients undergoing colorectal cancer surgery. To assess if treatment of anemia by transfusions can improve outcome, we conducted the present retrospective analysis.

Of all patients who underwent elective colorectal cancer surgery at the University Hospital of Innsbruck between 2010 and 2019, 654 patients could be included in the study. The impact of preoperative anemia and transfusion on 1‑year survival was assessed using Kaplan-Meier analysis, univariate and multivariate Cox regression and inverse probability treatment weighting models to estimate the effects of preoperative transfusion on outcome.

Preoperative anemia was present in 62.4% of patients and was the strongest predictor of perioperative transfusions. Intraoperative or postoperative transfusion occurred in 30.3% of the cohort, with higher rates in anemic patients. The transfusion rate was 36% between 2010 and 2015 and 25% in patients who underwent surgery from 2015 onwards.

The 1‑year survival was significantly lower in transfused compared to nontransfused patients. After adjusting for age, sex and hemoglobin, transfusions and anemia were no longer independent predictors of survival. Elevated C‑reactive protein (CRP), higher tumor stage, age and minimally invasive surgery were identified as the main independent predictors of 1‑year mortality.

Preoperative anemia predicts a higher rate of perioperative transfusions and is associated with worse 1‑year survival after colorectal cancer surgery. Transfusions do not correct impaired survival in patients with anemia. These findings underline the importance of proactive anemia management before surgery to improve postoperative outcome.