Early lung cancer patients advocate surgical treatment,while for patients who have reached a late stage,the main treatment is chemotherapy or radiotherapy.Because of its large side effects,many patients can not tolerate it.Molecular targeted therapies are now guideline-recommended treatments for unresectable non-small cell lung cancer (NSCLC) patients harboring driver gene mutations as a front-line treatment.Avitinib,olmutinib,and pelitinib are additional type VI inhibitors in clinical trials for non-small cell lung cancer that target EGFR.In comparison to standard chemotherapy,they can prolong not only progression-free survival but also overall survival [4–5].Confirmed by research [6–7],Activating mutations of the EGFR are a driving force for some lung adenocarcinomas.A comparison of only EGFR-TKI treated and received best supportive care patients with EGFR mutation revealed that the former had a three times longer median survival times than the latter.Patients with wild type (WT) EGFR,who constitute a larger proportion of NSCLC patients,derive limited clinical benefits from EGFR-TKIs [8–9].Therefore,it is very important to determine whether EGFR gene mutation exists in patients with advanced lung adenocarcinoma before treatment.Literature report [10–12] that female patients older or equal to 64 years with non-smoking habbit were more detected with EGFR mutations.The results showed that the EGFR gene mutation group was mostly female and non-smokers (P = 0.020),consistent with previous views.However,there is no correlation between age and EGFR gene mutation in this study,which may be related to the fact that the average age of this study is 62.91 ± 10.83,which is younger than the previous study group.
There are many studies between the basic characteristics of CT images and the mutation of lung adenocarcinoma gene. Hsu[13]considered that adenocarcinomas with wild-type EGFR were significantly associated with larger tumors and an irregular shape,calcification was more common in the tumors with wild-type EGFR than in those with EGFR mutations.Most studies [14–15] believe that patients with lesions presenting GGO or mixed GGO and air bronchograms on CT were more likely to exhibit EGFR mutations. Research supported [16–17] GGO, air bronchogram,vascular convergence, pleural retraction, spiculated margins are significant risk factors for EGFR mutation.However,some scholars[18]proposed that CT features such as tumor size,cavitation,air-bronchogram,lobulation and spiculation did not demonstrate statistically significant correlation with EGFR mutations individually (P = 0.91;0.67;0.12;0.45;and0.36,respectively).It may be due to the difference of inclusion criteria and the subjective evaluation of CT signs,but lacking objective criteria.DECT can provide lesion morphology and multiple quantitative parameters simultaneously.Since there are few interference factors in measuring the iodine of the tumor,it can reflect the blood supply and internal angiogenesis objectively.In this study,the iodine concentration of tumor in venous phase was measured by dual energy CT,the standardized iodine concentration and the slope of energy spectrum curve were calculated.The results showed that IC,NIC and k in EGFR mutant group were higher than those in wild group,and IC and k were statistically significant(P < 0.05),The main reason may be that EGFR gene mutation leads to tumor neovascularization and blood supply increase.Previous reported [19] NIC can differed significantly in EGFR groups,this study are consistent with it.The NIC optimal cutoff value is 0.17,in addition,in this study,IC and k values in venous phase were correlated with EGFR mutation,and the optimal cutoff values were 1.55mg/ml and 2.06,respectively.
There were researches find [20–22] that serum CEA levels was associated with mutations of the EGFR gene in patients with lung adenocarcinomas.There is a positive correlation between serum CEA expression level and EGFR mutation status in NSCLC patients,namely the EGFR mutation-positive rate increases as the serum CEA expression level rises within a certain range(≥ 20ng/mL,especially 20~49ng/mL)[23–24].
Negative soluble fragment of cytokeratin 19 (CY21-1) levels were significantly associated with EGFR mutations(P < 0.05) [25].Serial testing of the concentration of CY21-1 could be a useful added tool for monitoring therapy response and early detection of disease progression in lung cancer patients[26].In this study,CEA in the mutant group was higher than that in the wild group, and the best cut-off value was 18.40ng/ml,while CY21-1 in the mutant group was lower than that in the wild group,and the best cut-off value was 3.63ng/mlHowever.Study had proposed that [27] a single metabolic parameter is not convincing enough,and multiple independent factors are required to jointly establish the EGFR mutation prediction model. Combined with the quantitative parameters of DECT,a logistic regression model was established to evaluate the EGFR gene mutation of advanced lung adenocarcinoma.The AUC value was 0.807.The efficiency of predicting EGFR gene mutation in patients with lung adenocarcinoma is higher than each single index and the combined value of dual energy parameters in venous phase,which maybe conducive to guide individualized treatment better.