Immunonutrition in elective colorectal surgery and early inflammatory response

Background: Immunonutrition has gained increasing interest over years, enough to be recommended in several international guidelines and to be included in the ERAS protocol for colorectal surgery. Although clinical advantages have been proved for malnourished cancer-affected patients, its role is more controversial in other settings. We evaluated the impact of immunonutrition in major colorectal elective surgery for benign and malignant diseases, regardless of the preoperative nutritional status. Methods: We conducted a single center retrospective analysis of a database of patients who underwent elective major colon-rectal surgery for benign and malignant diseases between January 2018 and February 2020. In January 2019 we started a protocol to define which patients should receive preoperative immunonutrition, regardless of their nutritional status. We compared early postoperative outcomes and laboratory data of this group (IMN) to those of patients who met all the characteristics to be included in the protocol, but who did not receive immunonutrition (CTRL). Results: The IMN group showed significantly lower total leukocytes and neutrophils values and a lower pathological leukocytosis rate on 1st postoperative day compared to the CTRL group (P=0.004). Although differences in early postoperative clinical outcomes were not significant, patients belonging to the IMN group needed less postoperative antibiotic treatment (P=0.047). Conclusions: Immunonutrition could affect granulocytopoiesis and neutrophils recruitment in damaged tissues. This could lead to better and faster tissue healing and, consequently, to a reduction in postoperative complications even in normo-nourished patients. The lower need for antibiotic treatment could reflect a reduced susceptibility to postoperative infections.