The Correlation Of Ki-67 Index, SUVmax And Risk Stratification Of NIH In Gastrointestinal Stromal Tumour

Objective:Through the preoperative examination of PET/CT with 18F-FDG as tracer in patients with GIST and postoperative pathologic diagnosis, risk stratification and immunohistochemical detection of Ki-67, the correlation of ki-67 index, SUVmax and risk stratification of NIH in GIST would be analyzed, in order to investigate the relationship between Ki-67 index and PET/CT in the judge of tumor cells’ proliferation activity, and further study on the estimated value of those two indicators in prognosis as well as efficacy assessment of molecular target therapy.Methods:1. Object selectionFrom December 2012 to December 2014 in our department, within a total of 142 patients suspected of GIST, we had selected those who had been informed consent and voluntarily required to check PET/CT before operation. A prior PET/CT had been performed and then, without any tumor-related treatment, the surgery resection had been directly completed. In addition, single tumor, R0 resection and confirmed as GIST by postoperative pathology and immunohistochemisrty all were the extra requirements.2. Case informationForm December 2012 to December 2014, within a total of 142 patients, 18 patients were selected. Among them, 13 male, 5 female; the age arranged from 40 to 78 years old, the average was 58.9 years old. Disease course ranged from 2 months to 10 months, average was 5.6 months. The primary sites: 6 cases in stomach, 3 cases in duodenum, 6 cases in jejunum and ileum as well as the mesentery, 2 cases in colon, and 1 cases in retroperitoneal. Postoperative pathological examinations confirmed 13 cases as spindle cell tumor, 2 cases as epithelial cell, 3 cases as mixed cell type. Immunohistochemistry showed that CD117 were all positive(+ ~ + + + +), 2 cases were CD34 negative, 3 cases were DOG-1 negative, 3 cases were SMA negative, 4 cases were S-100 negative, and 4 cases were Desmin negative.3. Preoperative PET/CT examinationAfter full preparation, the PET/CT using 18F-FDG as a tracer was performed. Then we selected the region of interest(ROI), and gained the maximum standardized uptake(SUVmax) of the lesions through automatically calculating by the computer program.4. Postoperative pathology and immunohistochemical examinationPostoperative pathological examination was performed to confirm the diagnosis of GIST, and to classify the risk stratification with the 2008 NIH criterion. Then, based on multi-sampling and slicing, with the method of Elivision, immunohistochemistry was implemented to obtain the largest Ki-67 index of specimens.5. Statistical methodStatistical analysis was performed through SPSS 19.0. The data of the three groups were recorded and analysed by Spearman rank correlation. The result was statistical significant when P<0.05.Results:1. The dataAll 18 patients with GIST, the SUVmax distributed from 1.8 to 31.1, the average was 7.4. Varying degrees positive immunoreactions were observed in the specimens after operation. The ki-67 index was 0.3% to 60%, with an average of 12.8%. According to the 2008 NIH criterion, 9 cases were low risk(50%), 1 case was medium risk(5.6%), 8 cases were high risk(44.4%).2. Correlation analysis between Ki-67 index and SUVmax of PET/CTThe correlation coefficient was 0.529, P=0.024<0.05. There was a statistically significant positive correlation between Ki-67 index and SUVmax.3. Correlation analysis between Ki-67 index and the risk stratificationThe correlation coefficient was 0.451, P=0.061>0.05. There was no correlation between Ki-67 index and the risk stratification.4. Correlation analysis between SUVmax of PET/CT and the risk stratificationThe correlation coefficient was 0.561, P=0.015<0.05. There was a statistically significant positive correlation between SUVmax and the risk stratification.Conclusions:1. The PET/CT using 18F-FDG as a tracer might assist or replace the ki-67 index for the prognosis of GIST and to evaluate the effect of molecular targeted therapy.2. In clinical works, compared with Ki-67 index, SUVmax might be more objective and accurate to reflect the proliferation activity of tumor cells, as well as more objective to evaluate the prognosis and the effect of treatment in GIST.