Study On Clinical Related Factors Of Complete Pathological Remission In Locally Advanced Rectal Cancer After Neoadjuvant Radiotherapy And Chemotherapy

Objective: Relevant data show that the incidence of colorectal cancer in China has increased in the past 20 years.And colorectal cancer ranks in the top five of malignant tumors in terms of morbidity and mortality,which seriously threatens the health of the people.Therefore,how to better protect people's health needs and improve the level of diagnosis and treatment of colorectal cancer is a serious problem facing medical workers in the field of colorectal cancer.Since the beginning of the 21 st century,neoadjuvant radiotherapy and chemotherapy combined with total mesorectal excision has become the standard treatment mode for locally advanced rectal cancer.Neoadjuvant chemoradiotherapy can not only make the tumors of most patients with locally advanced rectal cancer shrink and decline,but also make the tumors of some patients achieve complete pathological relief.Relevant studies have shown that the prognosis of patients with complete remission of pathology is better than that of patients without complete remission of pathology.Therefore,it is of great significance to study the related factors of complete remission of pathology in predicting the prognosis of patients in advance and putting forward individualized treatment plan,so as to intervene relevant factors,improve the complete remission rate of pathology,and further improve the overall survival and disease-free survival of patients with rectal cancer.The aim of this study was to investigate the clinical related factors of pathological complete remission(pCR)in locally advanced rectal cancer after neoadjuvant radiotherapy and chemotherapy.Methods : The clinical data of 120 patients with locally advanced rectal cancer treated by neoadjuvant radiotherapy and chemotherapy and surgery in the first ward of Gastrointestinal Surgery Center of Sichuan Cancer Hospital from January 2013 to December 2018 were retrospectively analyzed.Radiotherapy methods are conformal intensity modulated radiotherapy(IMRT)or image-guided conformal intensity modulated radiotherapy(IGRT).The radiotherapy regimen was long-term radiotherapy with a dose of 50 Gy/25 f(2 Gy/f QD for 5 consecutive days per week)or 50.4 Gy/28 f(1.8 Gy/f QD for 5 consecutive days per week).The chemotherapy regimens were capecitabine concurrent chemotherapy or oxaliplatin plus fluorouracil regimens(including mFOLFOX6 and Capox regimens).After 6 to 16 weeks of radiotherapy,total mesorectal excision was performed by laparoscopy or laparotomy.In this study,single factor analysis(chi-square test and t-test)and logistic two-class multivariate regression analysis were used to analyze the clinical related factors of complete pathological remission after neoadjuvant radiotherapy and chemotherapy.Results: In this study,a total of 120 patients were enrolled to complete neoadjuvant radiotherapy,chemotherapy and radical surgery,21 of whom(17.5%,21/120)achieved complete pathological remission.There were 25 clinical factors,Sex,age,BMI,pathological type,CEA and CA199 before radiotherapy,CEA and CA199 before radiotherapy,tumor size,smoking,alcohol consumption,preoperative T stage,preoperative N stage,family history,hypertension,diabetes mellitus,anemia during radiotherapy,triglyceride level,blood cholesterol level,intestinal obstruction,tumor circumference,chemotherapy regimen,distance between tumors and anus,bone marrow suppression during radiotherapy,interval between radiotherapy and chemotherapy and operation were studied.Univariate analysis showed that age was younger(P=0.007),CEA level before radiotherapy was less than 5 ug/L(P=0.029),no history of smoking(P=0.026),and the distance between tumors and anal margin was more than 6 cm(P=0.001),which was related to the high pCR rate of locally advanced rectal cancer after neoadjuvant radiotherapy and chemotherapy.Multivariate regression analysis showed that age,CEA level before radiotherapy,smoking history and distance from tumor to anal margin were independent clinical factors affecting pCR rate after neoadjuvant radiotherapy and chemotherapy for locally advanced rectal cancer.Age was younger(P=0.022),CEA level before radiotherapy was less than 5 ug/L(P=0.017),no smoking history(P=0.008),and distance from tumor to anal margin was more than 6 cm(P=0.001).The better pCR rate was obtained.When stratifying the smoking situation,it was found that the level of CEA before radiotherapy was higher than 0.05 in both smoking and non-smoking groups,and there was no statistical difference.It could not be considered that the level of CEA before radiotherapy had different effects on the pCR rate in smoking and non-smoking groups.In subgroup analysis of chemotherapy regimens,the P value was more than 0.05.It was not considered that there was a difference in pCR rate between mFOLFOX6 and CapeOX regimens after neoadjuvant radiotherapy and chemotherapy.Conclusion:Some patients with locally advanced rectal cancer can achieve complete pathological remission after neoadjuvant radiotherapy and chemotherapy.Age,CEA level before radiotherapy,smoking history and distance from tumor to anal margin were independent clinical factors affecting pCR rate after neoadjuvant radiotherapy and chemotherapy for locally advanced rectal cancer.Patients with younger age,CEA level before radiotherapy < 5 ug/L,no smoking history and distance from tumor to anal margin greater than 6 cm could obtain better pCR rate,which can be used to predict the pCR rate of locally advanced rectal cancer after neoadjuvant radiotherapy and chemotherapy.It can not be considered that the influence of CEA level before radiotherapy on pCR rate is different between smoking group and non-smoking group.It can not be considered that the effects of mFOLFOX6 and CapeOX regimens on the pCR rate of locally advanced rectal cancer after neoadjuvant radiotherapy and chemotherapy are different.