The Relationship Between The EGFR Gene Mutation And Malignant Mulmonary Focal Ground Glass Lesion (fGGL)

Objective: Focal ground glass lesion(fGGL)include focal ground glass opacity(fGGO)and ground glass nodule(GGN).Focal ground glass lesion(fGGL)is defined as focal areas of hazily increased lung attenuation,without obscuring the underlying vascular and bronchial structures by HRCT.If the lesion is regular and clear in boundary and round in shape,it is called ground glass nodule(GGN).According to the density of the lesion,the fGGLs are divided into pure type and mixed type.The pathogenic factor include bleeding,inflammation,atypical adenomatous hyperplasia(AAH),adenocarcinoma in situ(AIS),minimally invasive adenocarcinoma(MIA),lepidic predominant adenocarcinoma(LPA)and so on.Now,the molecular targeted therapy has become one of the important means in the treatment of advanced lung cancer and the mutation of EGFR gene is one of the most important predictors of the efficacy of the targeted drug TKIs.In recent years,early lung cancer is gradually increasing and accounted for most of the surgical clinical cases,and the relationships between EGFR gene mutation of early lung cancer and clinical factors are still reported less.In this retrospective study,we discussed and summarized the relationship between the mutation of EGFR gene and the clinical characteristics of malignant pulmonary focal ground glass lesions,and laid foundation for the future research.Methods: From August 2012 to February 2015,86 patients had surgical treatment in general thoracic surgery of Chang Zheng Hospital of Second Military Medical University(inclusion criteria: diagnosed with fGGL(fGGO/GGL)by CT examination two weeks before surgery and pathology of premalignant and lung adenocarcinoma).The related data we collected include general statistics of patients,imaging data,pathology reports,EGFR gene mutation test reports,CEA test reports,survival time(follow-up start time: the day of surgery;follow-up deadline: June 30,2015;terminal event: died of malignant lung fGGL)and other related information.We use chi-square test for count data between groups and SPSS 21.0 software for statistical analysis and survival curve.Results: The EGFR gene mutation rate of malignant pulmonary fGGL was 50%,the 19 exon 19 del mutation rate was 16.28%,21 exon L858 R and L861 Q mutation rate were 31.40% and 2.33%,and 20 exon mutation rate was 0%.The rate of EGFR gene mutation of female patients was higher than that of male patients,but the difference was not statistically significant(P>0.05).The rate of EGFR gene mutationof patients without smoking(54.67%)was higher than that of smoking patients(18.18%)and the difference was statistically significant(P<0.05).The rate of EGFR gene mutation of patients(age?60y)was higher than that of patients(age<60y)and the difference was statistically significant(P<0.05).There were no significant difference in EGFR gene mutation between the p-fGGL cases and m-fGGL cases(P>0.05).There were no difference of gender,tumor diameter,pathology,stage,involvement of pleura and number of lesion between the EGFR gene mutation group and wild-type group(P>0.05).Preoperative CEA positive rate was 8.14%(7/86),the EGFR gene mutation rate of CEA positive group was 42.86% and the EGFR gene mutation rate of CEA negative group was 50.63%,the difference was not statistically significant(P>0.05).Follow-up ended June 30,2015,all patients were alive,follow-up time(440.48 ± 186.61)days.Conclusion: The EGFR gene in patients with malignant pulmonary fGGL showed a higher mutation rate,up to 50%(43/86).The most common mutation of EGFR gene was 21 exon L858 R,the mutation rate up to 31.40%(27/86).There were no difference between the mutation of EGFR gene and clinical factors(except age and smoking)(P>0.05).By clinical factors(age and smoking status)to predict the EGFR gene mutation has some value,but the value is limited.There were no significant difference between the specific sites(19-del,L858 R,L861Q)of EGFR gene and the related clinical factors.In this research,the positive rate of tumor marker CEA was lower(8.14%)and there were no significant difference between the EGFR gene mutation and tumor marker CEA(P>0.05).By CEA to diagnose malignant lung fGGL and forecast the EGFR gene mutation is meaningless.In this research,the short-term survival probability of malignant pulmonary fGGL was 100%,there were no significant difference between the short-term survival probability of patients with malignant lung fGGL and mutational status of EGFR gene.Long-term survival probability was relevant or not and whether the EGFR gene can become the prognostic predictor of malignant lung fGGL needed to be confirmed by further studies.This study provide clinical reference data for the research of EGFR gene mutation in patients with malignant pulmonary fGGL on one hand,and provide important theoretical foundation for the targeted therapy of EGFR tyrosine kinase inhibitors(TKIs)in patients with malignant pulmonary fGGL on the other hand.