Influence of nutritional status on postoperative outcome in patients with colorectal cancer - the emerging role of the microbiome

Many patients with colorectal cancer are overweight. Even then, nutritional status is a frequently underestimated risk factor for perioperative complications. Enhanced Recovery after Surgery is the goal for perioperative management, and preoperative nutritional risk screening should be a standard. In case of nutritional risk, perioperative nutrition therapy should be started without delay and should follow recent guideline recommendations. The preservation of the microbiome has an emerging role in preventing postoperative anastomotic leakage and septic complications. The time window for recovery after neoadjuvant treatment for rectal cancer may be used for conditioning appropriate-risk patients in a "prehabilitation" program. In order to assess metabolic recovery and the prognosis for long-term survival, C-reactive protein/albumin ratio may be a promising parameter, which has to be validated in the future. This narrative review summarizes recent strategies and guideline recommendations.