Comparison Of Short-term Efficacy And Safety Of Neoadjuvant Chemotherapy Versus Neoadjuvant Chemoradiotherapy In Locally Advanced Rectal Cancer:Single-center Propensity Score Matching Analysis

Objective:To compare the safety and short-term efficacy of two treatment strategies,neoadjuvant chemotherapy(nCRT)and neoadjuvant chemotherapy(nCT)before surgery for locally advanced rectal cancer.Methods:Enrollment criteria of cases:(1)The age is 18-75 years old;(2)Perform colorectal endoscopy before treatment,and take pathology to diagnose rectal adenocarcinoma;(3)Undergo surgical treatment,and have a complete postoperative pathology report;(4)Rectal MRI was performed before treatment,and the clinical diagnosis was cT3-4N0 or cTl-4N1-2;(5)Preoperative colorectal endoscopy,the distance between the tumor and the anal margin is than 12cm;(6)The ECOG score is 0-1.The patient has no serious organ dysfunction {heart,kidney,liver,etc.),andcan tolerate preoperative neoadjuvant therapy and surgery.Exclusion criteria:(1)There is no colonoscopy or clear pathological diagnosis before treatment;(2)Distant metastasis or unclear metastasis status before surgery or during treatment;(3)The pelvic cavity or abdomen has received radiotherapy;(4)Multiple primary tumors;(5)Autnimmune diseases;(6)The neoadjuvant treatment has not been completed,or the TME operation has not been performed after the treatment;(7)Case data is incomplete.According to the above criteria,we collected a total of 120 patients with locally advanced rectal cancer admitted to the D epartment of Colorectal Surgery,Cancer Hospital of China Medical University from June 2017 to June 2020.According to the previous neoadjuvant treatment plan,the patients were divided into nenadjuvant chemotherapy group(nCT group)(35 cases)and neoadjuvant chemotherapy group(nCRT group)(85 cases).We used propensity score matching to obtain a balanced group with a 1-2 ratio of cases,including the nCT group(33 cases)and the nCRT group(66 cases).There was no statistical difference between the two groups in clinical baseline data such as age,gender,height,weight,tumor stage,and distance from the tumor to the anal margin(P>0.05).Patients in the NCRT group were treated with conventional concurrent chemora dintherapy,and surgery was performed 6-8 weeks after radiotherapy The nCT group was given Capox for at least 4 cycles or mFolfnx6 for at least 4 cycles before surgery.The incidence and efficacy of toxic reactions during the neoadjuvant period of the two groups were compared,and the safety at 30 days after the operation was compared.Resnlts:The 1-2 grade toxic reactions during nenadjuvant therapy in the nCRT group andnCT group mainly included anemia,decreased neutrophil count,decreased platelet count,abnormal liver function,and gastrointestinal dysfunction There was no statistical significance in the two groups(P>0.05).Additional radiation-related side effects occurred in the nCRT group,including 1 case of radiation intestinal injury,2 cases of radiation bladder injury,and 9 cases of radiation skin injury.After 99 patients received neoadjuvant treatment,the ORR.rate of the nCT group was 42.42%.and that of the nCRT group was 68.18%.All patients completed RO resection There was no significant difference in the anus preservation rate between the two groups(P>0.05),and there was no significant difference in the amouat of blood loss and the duration of the operation between the two groups(P>0.05).Among postoperative complications,the incidence of postoperative moderate and severe perineal pain in the nCRT group was significantly more than that in the nCT group,and the difference was statistically significant(P=0.002).There was no significant difference in pelvic infection.surgical incision infection,and postoperative intestinal obstruction(P>0.05)The length of time that patients in the nCT group wore the drainage tube was significantly lower than that in the nCRT group,and the difference was statistically significant P<0.0001)The proportion of protective fistulas in the nCRT group was significantly higher than that in the nCT group,and the difference was statistically significant(P<0.001).The nCRT group reduced the tumor st age and the tumor shrinkage was better than that of the nCT group,which was statistically different(P<0.001).Couchsion:For locally advanced rectal cancer,although preoperative neoadjuvant chemotherapy with Capex or mFolfox6 regimen alone has a lower pCR rate and ORR.rate than neoadjuvant chemoradiotherapy,the RO resection rate and anus preservation rate are not inferior to neoadjuvant cheamoradiotherapy.Inaddition,the neoadjuvant chemotherapy group has a low fistula rate,does not cause radiation damage,and has better perioperative safety.