Validation And Optimization Of ESMO Risk Stratification Model For Non-metastatic Rectal Cancer

BACKGROUND:The incidence of rectal cancer in China is increasing,which seriously threatens the health level and quality of life of residents.The promotion of standardized diagnosis and treatment of rectal cancer has improved the prognosis and survival of patients with rectal cancer.Risk stratification based on clinicopathological factors is regarded as the basis of refined and individualized treatment for rectal cancer.The 2017 European Society of Medical Oncology(ESMO)guidelines for colorectal cancer risk stratification strategies are widely used in clinical practice.T stage,N stage,mesorectal fascia(MRF),extramural vascular invasion(EMVI),distance from the anal verge,levator ani invasion,and lateral lymph node were mainly included as risk stratification factors.However,there is still a lack of relevant clinical data to confirm its effectiveness.OBJECTIVE:This study aims to preliminarily verify the effectiveness of the 2017 European Society of Medical Oncology(ESMO)guideline risk stratification strategy for rectal cancer,and try to optimize the preoperative risk stratification strategy by screening prognostic risk factors to promote the individualized diagnosis and treatment of rectal cancer.MATERIALS AND METHODS:The data of patients with rectal cancer who received surgical treatment in Peking University Cancer Hospital from 2007 to 2015 were collected,and patients without preoperative treatment and with complete clinicopathological data were included as subjects.Patients were stratified according to the 2017 ESMO Guidelines Risk Stratification Model for Rectal Cancer,and prognostic differences between risk groups were compared to verify the effectiveness of the model.Univariate and multivariate Cox proportional risk regression were used to screen out the risk factors closely related to the survival,recurrence and metastasis of patients,and then the preoperative risk stratification model of rectal cancer was constructed.Kaplan-Meier and log-rank test were used to compare the 5-year local relapse-free survival and 5-year distant metastasis-free survival among different risk groups.The study will also construct a postoperative survival prediction nomogram for rectal cancer based on postoperative related factors.RESULTS:The study eventually enrolled 296 patients with rectal cancer.According to the ESMO risk stratification strategy,they were divided into five groups:very early disease(1 case),early disease(31 cases),intermediate disease(87 cases),locally advanced disease(49 cases),and advanced disease(128 cases).ESMO stratification showed no significant difference in local recurrence-free survival,distant metastasis-free survival and overall survival,and the log-rank test results among groups were P=0.018,P=0.151,and P=0.145,respectively.Among these preoperative risk factors,distance from the anal verge,grade,extramural venous invasion(EMVI),carcinoembryonic antigen(CEA)were independent factors for the survival and prognosis of rectal.Only grade was closely associated with local recurrence(P<0.001).The distance from the anal verge,EMVI,CEA were independent factors of distant metastasis of rectal cancer.Combined with postoperative risk factor analysis,grade,pathological N(pN)stage,lymphovascular invasion(LVI)and CEA were independent prognostic factors for the survival of rectal cancer.Grade was closely associated with postoperative local recurrence(P<0.001).The distance from the anal verge,pN stage,CEA were independent factors of distant metastasis of rectal cancer.Based on the above-mentioned factors,preoperative risk stratification strategy for rectal cancer was constructed in this study.There were significant differences in local recurrence-free survival and distant metastasis-free survival among risk groups,and the log-rank test results were P<0.001.In this study,the nomogram of long-term survival after operation and distant metastasis-free survival of rectal cancer was constructed,and the C-index was 0.788 and 0.753,respectively.CONCLUSION:The 2017 ESMO rectal cancer risk stratification strategy was not valuable in differentiating differences in local recurrence,distant metastasis,survival outcomes of rectal cancer,and it still needs to be further optimized.The preoperative risk stratification model based on pathological grade,tumor distance from anal verge,EMVI and CEA can effectively distinguish the risks of postoperative local recurrence and distant metastasis in rectal cancer patients,and guide the selection of comprehensive treatment strategies.