Meta-analysis Of The Effect Of Lateral Lymph Node Dissection On The Prognosis Of Low Rectal Cancer

Objective:To analyze the effect of lateral lymph node dissection on the prognosis of low rectal cancer,and then to explore its significance in the treatment of low rectal cancer.Methods:Searching Chinese and foreign literatures published in The Cochrane Library,Pubmed and EMbase databases,and enrolling the Randomized controlled trials from January 2009 to December 2019 on whether lateral lymph node dissection was performed in addition to total mesorectal resection for low rectal cancer.Results:Finally,the Meta-analysis enrolling a total of 12 articles and 6356 patients with low rectal cancer.The patients were divided into two groups:LLND group and TME group.There were 2741 patients in LLND group and 3615 patients in TME group.There were 8 articles recording data on local recurrence,with a total of 4585 patients.There was no significant difference in local recurrence rate between LLND group and TME group(OR=0.76,95%CI[0.50,1.17],P=0.21,I~2=62%).There were 4 articles recording data on overall 5-year survival,with 3416 patients,and 5-year overall survival rate in LLND group was not significantly improved compared with TME group.There was no significant difference in 5-year overall survival(OR=1.15,95%CI[0.85,p=0.37,I~2=65%)compared with TME group,A total of 5 articles recorded the data of operation time and blood loss,with a total of 1777 patients.The operation time of LLND(MD=110.87,95%CI[101.55120.19],P<0.00001,I~2=64%)and blood loss(MD=157.95,95%CI[75.97239.93],P=0.0002,I~2=94%)were significantly higher than those of TME group,and the difference was statistically significant.There were a total of 4 articles recorded the data of postoperative urinary dysfunction,with a total of1458 patients.There was no significant increase in the incidence of postoperative urinary dysfunction complications in the LLND group compared with the TME group,and the difference was not statistically significant(OR=2.94,95%CI[0.97,8.92],p=0.06 I~2=82%).A total of 245 patients with postoperative sexual dysfunction were recorded in 2 literatures.The incidence of postoperative sexual dysfunction complications in the LLND group was not significantly higher than that in the TME group(OR=7.21,95%CI[0.26199.68],P0.24 I~289%),and the difference was not statistically significant.However,the overall incidence of postoperative dysfunction was significantly increased in the LLND group(OR=3.29,95%CI[1.40～7.77],P=0.007 I~2=82%),and the difference was statistically significant.Both the 3-year recurrence-free survival(OR=1.36,95%CI[0.80,2.33],P=0.25)and 5-year recurrence-free survival(OR=1.04,95%CI[0.81,1.34],P=0.77)in LLND group were not significantly improved compared with TME group.Then,a subgroup analysis was conducted on the effect of preoperative neoadjuvant radiotherapy and chemotherapy followed by surgery on the local recurrence.There was no significant improvement in the LLND group compared with the TME group.Among them,5 articles with 1912patients were involved in the neoadjuvant radiotherapy group before operation,and the local recurrence was OR=0.73,95%CI[0.38～1.41],P=0.35,I~2=38%,while in the non-neoadjuvant radiotherapy group,there were 2 articles with 2673 patients,the local recurrence rate(OR=0.78,95%CI[0.39～1.54],P=0.47,I~2=84%),The differences were not statistically significant.Conclusion:Compared with TME alone,TME+LLND can increase the operative time and blood loss in patients with low rectal cancer,and may increase the incidence of postoperative functional disorders.However,it can not significantly improve the local recurrence,3-year recurrence-free survival,5-year recurrence-free survival and 5-year survival.Therefore,LLND does not improve the prognosis of the patients with low rectal cancer,and the application value of LLND in patients with low rectal cancer still needs to be further clarified.