A Clinical Comparative Study Of Four Evaluation Criteria And Pd-L1 Assisted NIH2008 Improved In Assessing The Risk Of Postoperative Recurrence Of Gist

Objective:(1)To explore the application value of three classification criteria and nomogram with gastrointestinal stromal tumors in China.(2)To investigate the expression of PD-L1 in gastrointestinal stromal tumors,and the clinical observation of PD-L1 assists of the risk assessment for recurrence of gastrointestinal stromal tumors after operation and the prognosis evaluation of patients.Methods:(1)By collecting case files and follow-up to 163 cases of GISTpatients who were treated with surgically resected between January 2005 and July 2018 in the People’s Hospital of Guangxi Zhuang Autonomous Region,retrospectively analyze the clinical,pathological and survival data.(2)163 cases of GISTs were evaluated for their biologic potential by the risk-stratification criteria of Fletcher,Miettinen,NIH2008,using Kaplan-Meier survival analysis to compare Miettinen and Fletcher classification,establish logistic regression model and ROC curve analysis to compare the accuracy of Miettinen and NIH2008 classification.(3)The new nomogram model and calibration curve of postoperative recurrence-free survival rate were drawn according to the regression coefficients and other data of selected variables in the COX regression model.(4)Tumor tissue wax blocks were collected from 163 samples.The expression of PD-L1 was analyzed by immunohistochemistry.The relationship between PD-L1 expression and variousfactors was analyzed by statistical methods.Results:(1)The tumor-free survival time of the very low-risk group and the low-risk group of Fletcher,Miettinen and NIH2008 were significantly higher than those of the intermediate-risk group and the high-risk group(P<0.05),there was no significant difference in tumor-free survival time between extremely low-risk group and low-risk group(P > 0.05).There was no significant difference in tumor-free survival time between middle-risk group and high-risk group(P > 0.05).(2)Establishing the ROC of NIH2008 and Miettinen,the area under the curve(AUC)was 0.760 and 0.757,respectively.(3)Establishment of the new nomogram model and calibration curve:the new nomogram model and calibration curve were build using R language.The alignment pattern was close to a straight line with slope 1,and a nomogram can accurately predict the postoperative recurrence risk of GISTs.(4)There were significant differences in the expression intensity of PD-L1 between different tumor sizes and mitotic numbers(P < 0.05).There were no significant differences in the expression intensity of PD-L1 between different sexes,tumor sites and patient outcomes(P > 0.05).Conclusions:(1)Fletcher,Miettinen and improved NIH2008 can effectively assess the recurrence risk of patients after GIST,but Fletcher may misjudge the GIST in different parts,Miettinen and improved NIH2008 can be choosed one of them according to different situations.The nomogram can accurately predict the postoperative recurrence risk of GISTs.(2)The positive rate of PD-L1 expression in GIST tissues was high,but it was almost not expressed in normal human tissues.The expression of PD-L1 is related to tumor size and number of mitotic figures,but not related to tumor location,patient gender and age,there were significant differences in the expression of different risk groups in the NIH2008.It can not be used as an independent prognostic indicator,and its mechanism needs further study.