Optimizing Preoperative Anemia in Non-Metastatic Colorectal Cancer: A Systematic Review on Surgical Recovery and Outcomes

Abstract

Background/Objectives: Colorectal cancer (CRC) is among the most commonly reported malignancies globally, taking the third place in incidence among males as well as the second among females, with over 1.9 million new cases and 935,000 deaths estimated worldwide in 2020. One of the most common and clinically significant comorbidities in patients undergoing CRC surgery is preoperative anemia, with reported prevalence ranging from 23% to over 60% depending on the population and diagnostic criteria used. The objective of the current study is to systematically evaluate the current body of evidence on preoperative anemia management in adults undergoing surgery for non-metastatic CRC. This review aims to assess the clinical impact of different iron supplementation strategies, particularly IV versus oral iron in pre-operative hematologic optimization, transfusion requirements, postoperative complications, and recovery outcomes. Methods: The current systematic review was conducted based on the PRISMA for Systematic Reviews and Meta-analysis checklist. The study has been registered to PROSPERO with the ID CRD420251113455. Results: Across all studies, IV iron and erythropoiesis-stimulating agents emerged as safe and more efficient alternatives to iron per os, especially when initiated at least two weeks before surgery. Thus, highlighting the clinical value of proactive anemia management as a cornerstone of surgical prehabilitation, potentially reducing transfusion burden and improving recovery outcomes for CRC patients. Conclusions: It is observed that IV iron therapy offers a more effective strategy than per os supplementation for correcting preoperative anemia in non-metastatic colorectal cancer patients. Their hematologic benefits enhance surgical readiness and reduce postoperative intervention needs. Thus, supporting the integration of IV iron into preoperative optimization protocols.