This study identified the independent risk factors for benign anastomotic stricture following colorectal cancer surgery. Here, we analyzed clinicopathologic characteristics of 117 colorectal cancer patients undergoing the surgery from January 2015 to December 2019. These patients were classified as either the group with anastomotic stricture or that without the stricture. The statistical analysis revealed associations between anastomotic stricture and clinical variables including the anastomotic distance, protective stoma, anastomotic leakage, and LCA preservation. Moreover, multivariate logistic regression analysis identified anastomotic distance, protective stoma, anastomotic leakage, and LCA preservation as independent risk factors for benign anastomotic stricture. The predictive model used in the study was as follows: Logit (anastomotic stricture) = 0.074* LCA + 5.353* Protective stoma + 12.027* Anastomotic leakage + 7.578* Anastomotic distance. We showed that accurate assessment of anastomotic stricture risk could be made by using this predictive model.
It has been shown that the rate of benign anastomotic stricture, one of the most prevalent complications following surgery in colorectal cancer patients, is 8.7–13%[11–13]. Contrary to the previous reports, this study observed a rate of anastomotic stricture of 1.7%. In this case, it is difficult to compare the incidence of anastomotic stricture among different studies because of the different definition and diverse inclusion criteria of anastomotic stricture. So far, the definition of anastomotic stenosis remains inconsistent. In the present study, the diagnosis of anastomotic stenosis was made based on the following criteria: the 12-mm colonoscope could not pass the anastomosis; the digital rectal examination revealed that the index finger could not pass the anastomosis or there was an obvious palpable stenosis ring; the gastrointestinal angiography showed anastomotic stenosis (< 10mm). Further studies are required for standardization and categorization of anastomotic stricture.
Here, we identified anastomotic distance, protective stoma, anastomotic leakage, and LCA preservation as independent risk factors for benign anastomotic stricture. Consistently, Ashok Kumar et al demonstrated that decreased distance between the tumor and the anal verge serves as a risk factor for benign anastomotic stricture. L Polese et al looked at the rate of anastomotic stricture in 211 patients and identified anastomosis located between 8 and 12 cm away from the anal as verge risk factors based on the univariate analysis . It has been reported that pelvic floor surgery for low anterior rectal resection may produce enlarged wound area and decrease local anti-infection ability, resulting in compromised healing ability of the local tissue of the anastomosis [15, 16]. Moreover, low position of the anastomosis can affect its healing due to colonic ischemia following surgery [17, 18]. All these observations may explain why the rate of anastomotic stricture remains high.
The protective stoma has also been shown to affect the rate of the stricture following surgery for colorectal cancer. Consistent with the present study, multiple studies identified the presence of a stoma as an independent risk factor for anastomotic stricture[19, 20]. B P Waxman et al reported that dilatation due to fecal stream may be involved in prevention of anastomotic stricture. Thus, protective stoma could prevent the patients from benefiting from fecal dilatation. It has been demonstrated that protective stoma can cause a decrease in bowel movements, which may induce anastomotic stricture frequently. We, therefore, reason that early reacceptance and preventive finger expansion may effectively reduce the occurrence of anastomotic stricture.
Anastomotic leakage was another independent risk factor for benign anastomotic stricture. Multiple studies have shown that anastomotic leakage predisposes patients to develop anastomotic stricture [14, 23, 24]. Anastomotic leakage is a common and feared complication, while it could cause intense inflammation[23, 24], which may contribute to a high rate of the stricture. Moreover, formation of scars caused by the infected surrounding tissues and fibroblast collagen during the healing process of anastomotic leakage may frequently induce anastomotic stricture. Thus, prevention of anastomotic leakage could effectively decrease the occurrence of anastomotic stenosis, thereby promoting the safety and long-term prognosis of patients after surgery.
LCA preservation could reduce the rate of anastomotic stricture following colorectal cancer surgery. When conducting laparoscopic lymph node dissection around the inferior mesenteric artery with LCA preservation, the surgeon often ligates the mesenteric artery at the root to ensure the effectiveness of the operation. Niels Komen et al measured the colonic perfusion of patients undergoing rectal resection for malignancy, and found a significant increase in the blood flow ratio in the low tie group as compared to high tie group . Once both the inferior mesenteric artery and LCA are cut off during surgery for colorectal cancer, the blood supply for the anastomosis may become obstructed. Therefore, preserving LCA may effectively reduce the occurrence of anastomotic stricture through maintaining the blood supply for the proximal sigmoid colon . Further research is needed to evaluate its applicability and safety.