Colorectal cancer (CRC) is the most common tumor of the digestive system, and estimates of new cases and deaths from CRC in the United States in 2024 are 152,810 and 53,010, respectively (1). At present, the main treatment for CRC is surgical tumor removal, and there are mainly two ways to do that depending on the location of the tumor, namely left colectomy (LC) and right colectomy (RC) (2, 3). Depending on tumor characteristics and surgeon experience, there are still debates about what type of surgery to choose to treat transverse colon cancer (4). Enhanced Recovery After Surgery (ERAS) is widely used due to its applicability and safety. Many studies have shown that ERAS can help improve prognostic recovery after colorectal surgery. This multimodal stress minimization method has been repeatedly proven to be able to reduce morbidity after CRC surgery, improve postoperative recovery, and shorten median median post-operative stay (5, 6). ERAS aims to bring patients back to their preoperative state quickly after surgery through multiple efforts such as minimizing perioperative fasting, encouraging exercise, and strict pain control (7). However, it is worth exploring whether we should implement different ERAS protocols depending on the location of the colon tumor. The goal of this study is to initially explore whether there are differences in the ERAS process of patients undergoing LC or RC colon cancer surgeries.

Over the past two decades, there have been two major improvements/fundamental developments in the perioperative care of patients having colon surgeries, namely the introduction of laparoscopic surgery [formerly known as Fast Track (FT) surgery] and the implementation of ERAS protocols. Compared to open surgery, laparoscopic surgery results in a significantly shorter median post-operative stay and much less postoperative morbidity and pain. As reported in multiple randomized controlled trials, this is due to less surgical stress response (14, 15). And it is also found in several randomized studies evaluating the effect of ERAS protocols on the outcomes of elective colorectal surgery that the implementation of ERAS helps reduce complications and median post-operative stay and accelerate postoperative recovery (16, 17).

Studies have shown that improvement in postoperative recovery depends primarily on intraoperative factors (e.g., minimally invasive surgery and afferent nerve block) and postoperative interventions (e.g., early nutritional preparation and mobilization after “fast-track” surgery) (18). The purpose of postoperative interventions is to promote the recovery of physical functions and accelerate recovery. However, studies have shown that due to poor health and psychological burden (fear of interfering with the healing process and anxiety about the possible additional treatment of the underlying disease) in the postoperative period, it may not be the best time to ask patients to make significant changes in nutritional intake and exercise (19). In comparison, interventions in the preoperative phase (both physically and psychologically) may be more helpful for postoperative recovery and relieving some of the emotional distress associated with the anticipation and recovery process of surgery. Some studies have also shown that regardless of motor skills, patients who improved their physical functions through exercise before surgery recovered better thereafter (20). However, one-third of patients experienced deterioration before surgery. Despite exercises, these patients were still at risk of prolonged postoperative recovery. Poor preoperative physical conditions (fatigue, malnutrition, and physical performance), anxiety and depression are also important confounding factors that can lead to prolonged recovery (21, 22). These results indicate that exercise training alone is not enough to reduce stress responses in all patients, and it is also necessary to consider factors that can promote adaptation to exercises, such as nutritional preparation and coping behaviors. Based on the foregoing and our experience, we believe that personalized postoperative rehabilitation plans should be developed for different patients and rehabilitation treatment should be carried out according to the specific conditions of the patients. Early walking exercise, diet recovery, and aggressive pain control are important components of ERAS, and they have been shown to aid recovery after colorectal cancer surgery. Therefore, the ERAS protocols covered in this study all encourage patients to do walking exercise, active diet recovery, and pain control as early as possible.

In our study, there were no significant differences between the groups in terms of time to first ventilation or bowel movement and time to tolerate solid foods, and the composite marker PPOI showed a clear trend towards slow bowel recovery after RC. Postoperative ileus (POI) has no internationally accepted clinical definition. As a quasi-physiological state of coordinated bowel motility arrest after surgical intervention, it usually disappears on the third day after laparoscopic surgery (23). PPOI refers to the inadequate recovery of POI on day 3 postoperatively, which impedes efficient delivery of intestinal contents or tolerance of oral intake of food. We consider this metric to be more reliable than some other commonly used indicators: the timing of first ventilation and stool is an inaccurate marker of bowel recovery, as patients may pass a small amount of gas or stool on the first day postoperatively but still have paralytic ileus for two to three days after surgery (24). Therefore, understanding the potential dangers of PPOIs is clinically relevant and can help surgeons avoid PPOIs through specific measures such as the use of prokinetic drugs and adjustment of postoperative food intake. In addition, the use of MBP may cause a delay in the first bowel movement. Times to solid food tolerance and appetite recovery may also be unreliable and subjective markers of bowel function recovery, as they lack quantitative definitions (25). Therefore, if these markers were used alone, the sensitivity to measure intestinal recovery would be low, and the curve of differences between groups would flatten. For these reasons, we believe that composite PPOIs are more adequate in terms of the condition assessment of patients. In terms of intraoperative variables, fluid doses were higher in the LC group than in the RC group (P < 0.05). Compared with the RC group, the LC group had a higher intake of oral liquid at the second POD, and faster first flatulence (P < 0.05). Postoperative complications occurred in 28.24% and 18.52% of patients with RC and LC, respectively, with no significant difference (P > 0.05). The main purpose of perioperative bowel preparation for colon cancer surgery is to rid the large bowel of solid feces and lower the bacterial content. However, this practice in fact liquefies the feces which increases the risk of surgical spilling and does not reduce the number of bacterial organisms in the bowel. This has been phased out in our latest ERAS agreement. The purpose of placing abdominal drainage is to observe and assist in the treatment of abdominal bleeding, anastomotic leakage, chyle leak, etc. after the surgery (to ensure adequate drainage and increase the success rate of conservative treatment). Therefore, in this study, there was no difference in the overall incidence of complications between the two groups, but there were differences between them in some specific complications, such as those requiring nasogastric tube insertion and the proportion of PPOI.