Anastomotic leak in colorectal surgery: Current evidence on risk, diagnosis, preventive measures and management

Anastomotic leak (AL) is a feared complication of colorectal surgery, associated with high morbidity, mortality and adverse oncologic outcomes. Despite advances in perioperative care, its incidence remains significant, and prevention is a central challenge in modern colorectal practice. This review summarizes the current evidence on AL with a focus on risk factors, diagnostic considerations and preventive strategies. Patient‐related risks include malnutrition, comorbidities, lifestyle factors and, more recently, alterations in the gut microbiota. Intraoperative contributors involve technical aspects of anastomosis construction, adequacy of vascular perfusion and procedure complexity, while postoperative risks relate primarily to delayed recognition and insufficient recovery pathways. Preventive measures span the entire perioperative continuum. Nutritional optimization, risk stratification and modulation of the microbiota represent key preoperative interventions. Intraoperatively, strategies emphasize meticulous technique, assessment of perfusion with emerging technologies and selective use of protective measures such as diverting stomas or transanal tubes. Postoperatively, standardized surveillance and adherence to enhanced recovery protocols are critical for early detection and mitigation of complications. Taken together, the evidence underscores that AL is a multifactorial complication requiring a multimodal prevention strategy. This review provides a structured overview of established knowledge and highlights evolving concepts, with the goal of informing both clinical decision‐making and future research.