| Background and Aims:Gastrointestinal stromal tumors(GISTs)are common digestive mesenchymal tissue–derived neoplasms that can appear in any part of the digestive tract.GISTs vary from benign to malignant phenotypes based on their biologic behavior.Patients with high malignancy potential phenotypes usually have poor prognosis,however,those with low malignancy potential phenotypes usually can survive for ages without suffering recurrence or metastasis.According to the current guidelines,surgical resection is the preferred treatment for localized GISTs,whereas,in recent years endoscopy resection has rapidly emerged as a toll for the management of GISTs and is generally considered a safe and effective treatment which is welcomed by patients.Nevertheless,endoscopic resection of high malignant GISTs should still be avoided,because the treatment,differing from surgical resection,can break the pseudocapsule of the tumor.Therefore,it is vital for endoscopist to predict which GISTs have high malignancy potential before endoscopic treatment.Unfortunately,at present,we cannot judge the aggressiveness of GISTs before final pathology,which demonstrates its hysteresis quality in guiding treatment.Although high-risk Endoscopic ultrasonography(EUS)features are suggested to predict high malignancy potential GISTs,the criteria for identifying high-risk EUS features largely rely on the expertise of endoscopists and have therefore remained subjective.The accuracy of diagnosis of high malignant GISTs is not satisfactory by the method alone.Objectives:1.To investigate new independent risk factors for high malignancy potential gastric GISTs before endoscopic resection.2.To investigate new independent risk factors for high malignancy potential gastric GISTs less than 5 cm before endoscopic resection,then establishing and validating a simple model to predict high malignancy potential GISTs.Methods:1.Univariate and multivariate logistic regression analyses were performed in the cohort of 362 GISTs to investigate new independent risk factors.2.In developing cohort(275 GISTs less than 5 cm),univariate and multivariate logistic regression analyses were performed to investigate new independent risk factors.To establish the model,we assigned weighted points proportional to theβregression coefficient value for the factors determined in the multivariate analysis.Tumors size,which was categorized at 1 cm intervals,and factors identified in the multivariate prediction model were used as the test variables;the modified National Institutes of Health(NIH)classification system was used as the state variable to plot the receiver operating characteristic(ROC)curve.The Delong method was used to compare the two Area Under Curves(AUCs).In validation cohort(186 GISTs less than 5 cm),tumors size,which was categorized at 1 cm intervals,and factors identified in the multivariate prediction model were used as the test variables;the modified NIH classification system was used as the state variable to plot the ROC curve.The Delong method was used to compare the two AUCs.Results:1.The univariate analysis indicated significant differences between the high and low malignancy potential groups with regard to tumor size,tumor shape,mucosal ulceration and high risk ultrasonography features(P<0.05).The multivariate logistic regression analysis indicated that tumor size larger than 5 cm,irregular tumor shape,and mucosal ulceration were independent risk factors for high malignancy potential gastric GISTs(P<0.05).2.In developing cohort,the multivariate logistic regression analysis indicated that tumor size larger than 2 cm,irregular tumor shape,and mucosal ulceration were independent risk factors for high malignancy potential gastric GISTs less than 5 cm(P<0.05).Then the regression coefficients of the 3 independent risk factors were scored by linear transformation.Therefore,mucosal ulceration,irregular tumor shape,and tumor size larger than 2 cm were given scores of 1,2,and 3,respectively.The model score was assessed by ROC curve,and the optimal cutoff value was 4 points.The incidence rate of high malignancy potential GISTs was 13%in the low-grade risk group(0-3 points)and 48%in the high-grade risk group(4-6 points).There was a significant difference between the 2groups according to the chi-square test(χ~2=38.27 and P<0.001).The multivariate prediction model was used as the test variable and the modified NIH classification system as the state variable to plot the ROC curve.The AUC value was 0.79(95%confidence interval[CI],0.74-0.84).In contrast,when tumor size,which was categorized at 1 cm intervals,was used as the test variable,the AUC value was 0.73(95%CI,0.67-0.78),which was significantly lower than the value achieved using the multivariate prediction model as the test variable(P=0.008).In validation cohort,the incidence rate of high malignancy potential GISTs was 10%in the low-grade risk group(0-3 points)and 42%in the high-grade risk group(4-6 points).There was a significant difference between the 2 groups according to the chi-square test(χ~2=23.69 and P<0.001).The multivariate prediction model was used as the test variable and the modified NIH classification system as the state variable to plot the ROC curve.The AUC value was 0.80(95%CI,0.73-0.85).In contrast,when tumor size,which was categorized at 1 cm intervals,was used as the test variable,the AUC value was 0.73(95%CI,0.67-0.80),which was significantly lower than the value achieved using the multivariate prediction model as the test variable(P=0.034).Conclusions:1.A relatively large tumor size,mucosal ulceration,and an irregular tumor shape are independent risk factors for patients with high malignancy potential gastric GISTs.2.A tumor size larger than 2 cm,mucosal ulceration,and an irregular tumor shape are independent risk factors for patients with high malignancy potential gastric GISTs smaller than 5 cm.Moreover,these 3 factors can be applied to establish a simple-to-use preoperative predictive model that could help clinicians predict the malignant potential of gastric GISTs smaller than 5 cm. |
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