Effects Of Interval Between Neoadjuvant Chemoradiation Therapy And Radical Surgery On Short And Long Term Outcome For Local Advanced Rectal Cancer

Objective:To invesgate whether the time interval between neoadjuvant chemoradiotherapy and surgery affects the short and long term outcome.Methods:We restrospectively studied 441 patients diagnosed local advanced rectal cancer by pathological examination who underwent neoadjuvant chemoradiotherapy and added one period chemotherapy during waiting time followed by radical surgery between May 2008 to October 2014 at Department of colorectal surgery in Fujian Union Hospital.They were divided into two groups according to time interval:SI group(≤8 weeks)and LI group(>8 weeks).Clinical data were restrospectively reviewed to invesgate whether the time interval affects the short and long term outcome.The categorical variables were compared using χ2 test and Fisher’s exact test.Continuous variables were compared using t test.Logistic regression was used to identified factors influencing RCRG I+II grades.The survival curve was drawn by Kaplan-Meier method and the survival rate was analysed using the Log-rank test.Results:1.Patients characteristics:No statistically significant differences of sexuality、age、BMI、tumor makers、clinical staging with imaging、distance of tumor、parameters of tumor(P>0.05).2.Intraoperative postoperative status:(1)Intraoperative status:The rate of laparascopic surgery was significantly higher in LI group(P=0.01)and no statistically significant differences in sphincter-preservation rate、anastomosis site、operative time、rate of conversion to open surgery(P>0.05).(2)Postoperative intestinal function recovery time:Shorter defecation time were found on LI group(LI:2.63 d vs SI:3.27 d,P<0.001)(3)Postoperative comlications:No significant differences in overall complication rate、anastomotic leakage rate、postoperative ileus rate etc(P>0.05).Incision infection rate was significantly higher in LI group(LI:6.6% vs SI:1.3%,P=0.005)and rate of intestinal obstruction caused by pelvic fibrosis was also significantly higher in LI group(LI:1.7% vs SI:1.3%,P=0.047).In subgroup analysis,higher rate of urinary complications and longer operation time were found in the group which time interval was extended over ten weeks.3.Pathological examination:(1)No significant differences in pathological stage、p CR rate、positive resection margin rate etc(P>0.05).(2)Better tumor response was found in LI group(RCRG I+II: LI:97.3% vs SI:85.4%,P=0.003).(3)Metastatic lymph-nodes were less in LI group(LI:0.71 vs SI:1.36,P=0.029),especially in first lymph-node drainage station(LI : 0.56 vs SI : 1.12,P=0.016).Multivariate analysis showed time interval(P=0.001,OR:3.889,95%CI:1.685-8.973)、tumor in posterior rectal wall(P=0.009,OR : 0.197,95%CI : 0.059-0.665)were independent factors.4.Long-term outcome:No significant differences in DFS(SI:57.6% vs LI:61.1%,P=0.492)and OS(SI:94.0% vs LI:80.3%,P=0.100)in both groups.Conclusions:1.Prolonging time interval over 8 weeks lead to shorter postoperative intestinal recovery time,but increasing incisional infection and intestinal obstruction caused by pelvic fibrosis rate.2.Further extending time interval over 10 weeks caused longer operating time and higher rate of urinary complications.3.Waiting over 8 weeks after n CRT did not increase rate of p CR,yet inceasing RCRG I+II grades rate.4.Tumor in posterior rectal wall and time interval over 8 weeks were independent factors affecting RCRG I+II grades.5.Waiting over 8 weeks after n CRT did not change long-term outcome.