Establishment Of A Survival Prediction Model For Gastric Adenocarcinoma Patients Undergoing Surgery Combined With Chemotherapy

Background:Gastric cancer is one of the common malignant tumors of digestive tract,and its pathological type is mainly adenocarcinoma.Surgery is the only radical treatment at present,early gastric cancer patients can get a good prognosis after operation,and advanced patients need surgery according to pathological types and clinical stages,combined with perioperative chemotherapy,radiotherapy,biological targeted therapy as auxiliary comprehensive treatment,in order to prolong life and improve the quality of life.As most of the patients with early gastric cancer have no obvious clinical symptoms and are limited by the level of diagnosis and treatment,at present,most of the patients with advanced gastric cancer are advanced gastric cancer,and patients with advanced gastric cancer generally need preoperative or postoperative adjuvant chemotherapy.At present,it is difficult to accurately estimate the survival time of gastric adenocarcinoma patients who receive surgery combined with chemotherapy In the past,clinicians often make judgments according to patients' age,AJCC stage,postoperative pathology and other factors,combined with their own clinical experience,and the prediction results are often subjectively influenced by doctors.Scientific and accurate evaluation of the prognosis of gastric adenocarcinoma patients undergoing surgery combined with chemotherapy is helpful for clinicians to give reasonable and safe treatment according to the prognosis of the patients.At present,the survival prediction model for patients with gastric adenocarcinoma has been established,but it can not reflect the survival difference of patients with surgery combined with chemotherapy in detail.So far,a disease-specific survival prediction model for gastric adenocarcinoma patients undergoing surgery combined with chemotherapy has not been established.Objective:The Surveillance,Epidemiology and results Database(SEER database)was used to establish a nomogram of survival prediction model for gastric adenocarcinoma patients undergoing surgery combined with chemotherapy,so as to predict the survival rate of gastric adenocarcinoma patients receiving surgery combined with chemotherapy and guide clinical decision-making to a certain extentMethods:We extracted clinical information from the Surveillance,Epidemiology,and End Results SEER(the Surveillance,Epidemiology,and End Results SEER)of a total of 5,764 patients with gastric adenocarcinoma who underwent surgery and chemotherapy between 2004 and 2015,and used R software to randomly assign about 70%(n = 4034)of the included patients to the modeling group and the remaining30%(n = 1729)to the validation group.Cox risk ratio model was used to analyze the prognostic factors of patients undergoing surgery combined with chemotherapy.On the basis of Cox proportional risk model,a nomogram of survival prediction model was established.Then,the newly built model was validated with the data of the modeling group and the validation group:C index(the concordance index,C-index),the area under the receiver-operating curve(AUC),synthetic discriminant improve index(IDI)and net weight index(NRI)for evaluating the degree of differentiation,a new prediction model using calibration chart(Calibrations plot)calibration for survival prediction model established by the degree of evaluation,the final use decision curve analysis(DCA)by quantitative net income under different threshold probability to evaluate the clinical effectiveness of nomograph.Results :On the basis of multivariate analysis,a nomogram was developed that included age at diagnosis,number of regional lymph nodes,number of positive regional lymph nodes,ethnicity,tumor grade,AJCC staging,SEER comprehensive staging,and radiotherapy.It is calculated that the c-index of the new model is higher than that of the traditional seventh edition AJCC staging system(0.707 vs 0.661).The IDI and the net reclassification index(NRI)were significantly improved.The IDI of 3,5 and 10 years' disease-specific survival(DSS)were 0.058,0.059 and 0.058 respectively.The NRI of 3-year,5-year and 10-year DSS were0.380(95%ci = 0.316-0.470),0.407(95%ci = 0.350-0.505)and 0.413(95%ci = 0.336-0.519),respectively.The AUC of the new model modeling group and the verification group in year 3,5 and 10 were 0.744,0.746,0.743,0.744,0.747 and 0.75,respectively.The AUC of the seventh edition AJCC staging system modeling group and validation group are 0.690,0.686,0.678,0.685,0.692 and 0.717,respectively.The calibration plot,to a certain extent,reflects the good consistency between the predicted survival rate and the actual survival rate.The analysis of the decision curve shows that the constructed lineplotting system is superior to the AJCC staging system.Conclusions:The nomogram established in this study provides a reliable tool for predicting disease-specific survival in patients with gastric adenocarcinoma undergoing surgery combined with chemotherapy.According to the verification,the new nomogram will help to promote the individual survival prediction of gastric adenocarcinoma patients undergoing surgery combined with chemotherapy,make the prediction results more accurate,and provide guidance for clinical decision-making of gastric adenocarcinoma patients receiving surgery combined with chemotherapy.