| Objectives:To systematically evaluate the effect of delayed surgery and non-delayed surgery on the survival outcome,surgical outcome and postoperative complications outcome after neoadjuvant chemoradiotherapy for locally advanced rectal cancer,and provide evidence-based medical basis for the optimal time interval to surgery after neoadjuvant chemoradiotherapy to guide the clinical treatment of rectal cancer.Methods:The Pubmed,Embase,and Cochrane Library databases were searched on a computer to screen for clinical studies comparing postoperative neoadjuvant chemoradiation with delayed surgery and non-delayed surgery for locally advanced rectal cancer.The publication date of the search literature was updated to April 2018.Two reviewers independently selected literature,extracted data,and assessed the quality of literature included in the study.Then,meta-analysis was performed by using RevMan 5.3 software.Results:This study included a phase ? non-randomized controlled study and 10 cohort studies.A total of 31,496 patients were included,including 12,365 patients in the>8-week group and 19,131 patients in the<8-week group.There was no significant differences in the proportion of clinical ?/? cases between the two groups(P>0.05).Meta-analysis showed that the the>8-week group had higher pathological complete response rate[RR=1.26,95%CI(1.17,1.36),P<0.00001],lower sphincter preservation rate[RR=0.97,95%CI(0.95,1.00),P=0.03],and lower incidence of intestinal obstruction[RR=0.61,95%CI(0.38,0.99),P=0.04]than those of the<8-week group,with significant differences;while in terms of overall survival[RR=0.97,95%CI(0.85,1.11),P=0.65]disease-free survival[RR=1.05,95%CI(0.88,1.27),P=0.58],local recurrence rate[RR=0.86,95%CI(0.35,2.09),P = 0.74],operative time[MD =-0.35,95%CI(-8.87,8.16),P = 0.94],resection margin positive rate[RR = 0.97,95%CI(0.54,1.76),P = 0.92],incidence of anastomotic leakage rate(RR = 0.57,95%CI(0.23,1.38),P = 0.21)and incidence of urinary retention rate[RR =1.71,95%CI(0.75,3.86),P = 0.20],there was no statistically significant differences between the two groups.In addition,the complementary meta-analysis of this study included a total of 4 cohort studies,including 765 patients in the>12-week group and 3296 patients in the 12-week group.There was no significant difference in the proportion of clinical ?/?cases between the two groups(P>0.05).The complementary meta-analysis showed that in terms of pathological complete response rate[RR=1.07,95%CI(0.68,1.69),P=0.77],sphincter preservation rate[RR=0.91,95%CI(0.46,1.82),P=0.79],and resection margin positive rate[RR = 0.87,95%CI(0.25,3.04),P = 0.83].there was no statistically significant differences between the two groups.Conclusions:This meta-analysis believes that it is safe and feasible to perform total mesorectal excision at intervals of 8-12 weeks after neoadjuvant chemoradiation in locally advanced rectal cancer.The waiting period of 8-12 weeks after neoadjuvant chemoradiation can lead to higher pathological complete response rate in patients with rectal cancer,but there is a great risk of improving the survival outcome only by delaying the waiting interval.For patients with low rectal cancer,especially low rectal cancer patients who are insensitive to neoadjuvant chemoradiotherapy,delayed surgery more than 8 weeks may make some patients miss the opportunity to save the anus and increase the risk of permanent ostomy.At present,the clinical routine is not recommended to delay the surgical interval beyond 12 weeks.The effect of delayed surgery after neoadjuvant chemoradiation for more than 12 weeks on postoperative complications and long-term survival outcomes in patients with rectal cancer requires future large-sample,multi-center clinical randomized controlled trials to observe and verify. |
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