The Efficacy And Safety Of Intraoperative Radiotherapy In Rectal Cancer Resection: A Systematic Review And Meta-analysis

Objective: In recent years,more and more intraoperative radiotherapy(IORT)has been used in the adjuvant treatment of rectal cancer.However,there are still controversies about the efficacy and safety of intraoperative radiotherapy for rectal cancer.To solve this problem,we conducted a Meta-analysis of the published clinical controlled studies of intraoperative radiotherapy for rectal cancer and evaluated the efficacy and safety of intraoperative radiotherapy in adjuvant treatment of rectal cancer.Methods: Electronic databases Pub Med,EMBASE,the Cochrane Library,web of science,China National Knowledge Infrastructure(CNKI),Wanfang database and China biomedical medicine(CBM)were searched until July 2020 in English.To collect all the clinical controlled studies at home and abroad on the comparison of IORT and non IORT in radical resection of rectal cancer,extract the required data,evaluate the research methods and design,and use Stata 15.0 software for Meta-analysis.For binary variables,Odds Ratios(OR)and 95% confidence interval(95% CI)were used for analysis,while survival index was described by Hazard Ratios(HR)and 95% CI,and heterogeneity and publication bias were examined.Results: a total of 15 studies were included,including 3 randomized controlled trials(RCTs)and 12 observational studies involving 1460 patients with rectal cancer(687 in the IORT group and 773 in the non IORT group).In terms of efficacy,Meta-analysis showed that there was no significant difference in 5-year overall survival rate(HR = 0.80;95% CI = 0.60-1.06,P = 0.189)and 5-year disease-free survival rate(HR = 0.94;95% CI = 0.73-1.22,P =0.650)between IORT group and non IORT group,while there was significant difference in 5-year local control rate(OR = 3.07;95% CI = 1.66-5.66;P = 0.000).For safety,the results of Meta-analysis showed that the incidence of postoperative abscess(OR = 1.10;95% CI: 0.67-1.80,P = 0.833),postoperative fistula(OR = 0.79;95% CI = 0.33-1.89,P = 0.600),postoperative wound related complications(OR = 1.02;95% CI = 0.52-2.02,P = 0.948),postoperative anastomotic leakage(OR = 1.09;95% CI = 0.59-2.02,P = 0.775)and postoperative neurogenic bladder dysfunction(OR = 0.69,P = 0.000),95% CI = 0.31-1.55,P= 0.369).Conclusion: Our results show that the addition of intraoperative radiotherapy to the traditional multimodal treatment strategy can improve the local control rate,but it cannot significantly improve the survival rate of patients with rectal cancer.In the future,welldesigned prospective randomized controlled trials are needed to better define the therapeutic effect of intraoperative radiotherapy.