Analysis Of Clinicopathological Features And Gene Mutation On Prognosis In Patients With GIST And EGIST

Objective:To explore the relationship between the clinicopathological characteristics of Gastrointestinal stromal tumor（GIST）and Extragastrointestinal stromal tumor（EGIST）and the prognosis,and to study the relationship between the mutation of c-kit and PDGFRA gene in EGIST and the prognosis,in order to provide individualized treatment for patients with gastric stromal tumor.Method:The clinicopathological data of patients with gastrointestinal stromal tumors treated in the second hospital of Jilin University from January2010 to January 2020 were collected.The survival time of patients was followed up.According to the survival time,Kaplan-Meier survival curve was drawn to evaluate the impact of clinicopathological factors on the prognosis of patients.Cox proportional hazards model was used to analyze the impact of multiple factors on the prognosis of GIST patients.Result:（1）In GIST group,330 patients were successfully followed up and64 patients were lost.The follow-up rate was 83.8%.The follow-up time was 6-129 months.The 1-year,3-year and 5-year survival rates were94%、83%、71% respectively.Univariate analysis: tumor location,tumor diameter,mitotic image,risk,tumor rupture,invasion of surrounding tissues,Ki-67%,whether to take Glivec were related to the survival rate of GIST patients（all P < 0.001）;Multivariate analysis: tumor diameter,mitotic image,tumor rupture,risk and whether to take Glivec were correlated with the survival rate of GIST patients（all P < 0.05）.（2）27 patients in EGIST group were successfully followed up,and the follow-up rate was 100%.The patients were followed up for 5-135 months.The 1-year,3-year and 5-year survival rates were 89%、65%、47% respectively;Univariate analysis: mitotic image（P = 0.017）,tumor rupture（P = 0.044）and tumor invasion of surrounding tissues（P = 0.046）were associated with the survival rate of EGIST patients.Multivariate analysis: risk（P = 0.026）,tumor diameter（P = 0.045）,mitotic image（P =0.029）and tumor rupture（P = 0.042）were correlated with the survival rate of EGIST patients.（3）The average survival time of 330 GIST patients was 106.00 ±2.67 months,and that of EGIST patients was 63.00 ± 7.55 months.Univariate analysis showed significant differences in mitotic image（P =0.017）,tumor diameter（P = 0.040）,risk（P = 0.022）and CD34（P =0.017）.Compared with middle and high-risk gist,EGIST has higher mitotic image,larger tumor diameter,higher risk and stronger expression of CD34.The prognosis of patients with EGIST is poor compared with the 1 / 3 / 5-year survival rate of GIST.The difference was statistically significant（P < 0.01）.（4）In 27 patients with EGIST,14（51.8%）cases of c-kit mutation and 6（22.2%）cases of PDGFRA mutation were detected,all of which were exon 18 D842 V mutations.There were 7 cases of wild type（25.9%）.Among the patients with c-kit mutation,11（78.6%）had mutations in exon 11 and 3（21.4%）had mutations in exon 9.The average survival time of exon 11 mutants was 75.26±9.25 months,that of exon 9 mutants was 43.40±10.57 months,that of exon 18 mutants was 29.67 ±10.87 months,and that of wild type patients was 30.67±10.87 months.Among the patients with exon 11 mutation,the main mutation forms of exon 11 include deletion mutation,insertion mutation and point mutation.Among them,deletion mutation in 6 cases（54.5%）was the most common,followed by insertion mutation in 3 cases（27.3%）,and finally point mutation in 2 cases（18.2%）.The prognosis of patients with deletion mutation was worse than that of patients with insertion mutation and point mutation（P = 0.016）.Conclusion:（1）Tumor diameter,mitotic image,tumor rupture,risk and postoperative administration of Glivec are independent factors affecting the prognosis of GIST patients.（2）Risk,mitotic image,tumor rupture and tumor diameter are independent factors affecting the prognosis of EGIST patients.（3）EGIST patients have a worse prognosis than GIST.（4）The gene mutation frequency and site of EGIST are similar to GIST.The most common mutation site is c-kit exon 11,in which the deletion mutation type has the worst prognosis.