Ana B. Martínez-Martínez, Faculty of Medicine, University of Zaragoza, Zaragoza, Spain Jose M. Arbonés-Mainar, Institute for Health Research Aragón (IIS Aragón), Miguel Servet Hospital. Zaragoza, Spain

Introduction: Colorectal cancer is the second most frequent cause of deaths from cancer worldwide. Enhanced recovery protocols (ERPs) were developed in 90s to improve the recovery of these patients. Within ERPs, this work aims to compare immune response between open and laparoscopic procedures to support the best surgical approach. Materials and methods: The immune status of 148 patients undergoing colorectal surgery (74 by laparoscopic and 74 by open surgery [OS]) was studied in three moments: before surgery (POD0) and on the 1st and 3th post-operative days (POD1 and POD3). Results: Comparing to the laparoscopic group, in the OS group, C-reactive protein levels were significantly higher on POD1 and POD3 (p < 0.001), whereas lymphocyte levels were significantly lower (p = 0.006) and neutrophil levels were higher (p = 0.012) on POD1. On the other hand, higher levels of B cells (p = 0.023) were observed on POD1 in the laparoscopic group. Natural killer cell levels were significantly reduced (p = 0.034) in this group on POD3. Conclusions: Within the ERP, immune response pattern in both surgery approaches appears to be similar. Nevertheless, a greater inflammatory response of the OS is observed, whereas earlier recovery of the immune levels baseline seems to be a trend in the laparoscopic surgery.

Keywords: Immune response after surgery. Enhanced recovery protocols. Colorectal cancer surgery. Laparoscopic and open surgery.