A Correlation Research Of CT Features And Ki-67 Index,Risk Stratification In Gastrointestinal Stromal Tumor

Objective: To investigate the correlation between CT features and Ki-67 index,risk stratification in gastrointestinal stromal tumor(GIST).Methods: The clinicopathological and imaging data of 464 patients with primary GIST who underwent CT examination at the Affiliated Hospital of Qingdao University and confirmed by operation,pathology and immunity from January 2012 to October 2019 were analyzed retrospectively.We collected the baseline characteristic data(age,sex),the pathological data(pathological tumor diameter,mitotic image,Ki-67 index)and CT signs(location,size,boundary,outline,growth pattern,density,necrosis or cystic changes,calcification,ulcer)of every participants.Ki-67 index was divided into Ki-67≤5% and>5%groups;GIST patients were divided into extremely low,low,medium and high risk groups according to tumor pathological size,mitotic image count,tumor location and tumor rupture.Single factor analysis,Logistic multivariate regression analysis and Spearman rank correlation analysis were used to investigate the correlation the correlation between CT signs and Ki-67 index,risk stratification in gastrointestinal stromal tumor.Results:(1)The CT signs of gastrointestinal stromal tumors among different Ki-67 groups were analyzed by single factor.We found that CT imaging features including tumor size,margin of tumor,contour,necrosis or cystic degeneration were significant differences in Ki-67 index(P<0.001),and were positively correlated with the Ki-67 index(r=0.405 、0.446、0.328、0.326,P<0.05).The difference of growth pattern,density,ulcer and Ki-67 index was statistically significant(P<0.001),but the correlation with the Ki-67 index was weak(r=0.173 、 0.259、0.177,P<0.05).There was no significant difference between calcification and Ki-67 index(P>0.05).(2)Through multi-factor Logistic regression analysis,it was further found that tomor size > 4.65cm(OR=1.163,95%CI=1.055-1.282,P < 0.05)and the unclear boundary(OR=3.701,95%CI=2.185-6.269,P < 0.001)were effective variables in distinguishing between the groups with Ki-67≤5% and >5%.(3)Through statistical analysis of the risk classification of different Ki-67 groups,we found that the Ki-67 index was positively correlated with pathological tumor diameter,mitotic image,tumor site and risk stratification(r=0.383、0.508、0.143、0.481,P<0.05).(4)The gender and CT signs of patients with gastrointestinal stromal tumors of different risk grades were statistically analyzed.For the four different grade of GIST,there were significant differences in the tumor size,location,margin of tumor,contour,mode of growth,density,necrosis or cystic degeneration of CT(P<0.05),and positively correlated with risk stratification(r=0.809、0.336、0.551、0.495、0.353、0.373、0.539,P<0.05).There was significant difference between ulcer and risk stratification(P<0.001),but there was a weak correlation between ulcer and risk stratification(r=0.216,P<0.05).There was no significant difference in calcification,gender and risk stratification(P>0.05).Conclusion:(1)Tumor diameter > 4.65 cm and unclear borders are independent risk factors to judge Ki-67 index >5%.(2)The Ki-67 index is positively correlated with risk classification,mitotic figures,tumor location,and tumor diameter,reflecting that Ki-67 index can be used as an important reference index for evaluating GIST risk classification.(3)The size,location,boundary,outline,growth pattern,density,necrosis or cystic changes of CT masses are positively correlated with the risk classification,which is helpful to assess the risk classification of GIST.