Xican Gao¹, Qian Cai², Ruiguang Zhang², Yong He³, Fan Tong², Chunhua Wei², Jihua Dong², Gang Wu²

¹Oncology department,Cancer Center, union   Hospital, Tongji Medical College,HuaZhong University of Science and Technology, ²union   Hospital, CancerCenter,³Nuclear Medicine andPET, Nuclear Medicine and PET

Objective:Several phase Ⅲ studiesdemonstrated that, compared with traditional chemotherapy, epidermal growthfactor receptor-tyrosine kinase inhibitors (EGFR-TKIs), asfirst-linetreatments, contributed to protracted progression-free survival (PFS)and higher responserate (RR) in inhibitor-sensitive EGFR mutant patients.However, it is sometimes difficult to obtain sufficient tumor tissues forgenetic tests and, in some cases, invasive tests are not feasible. The aimof this study is to evaluate the relationship between the maximum standardizeduptake value (SUVmax) by ¹⁸F-Fluorodeoxyglucose (FDG) and serumcarcinoembryonic antigen (CEA) levels before initial treatment are associatedwith EGFR mutations in non-small cell lung cancer (NSCLC) patients. Method: Weincluded 167 patients with definite pathological diagnosis of NSCLC who underwent ¹⁸F-FDG PET/CT scan, EGFR mutation analysis by amplificationrefractory mutation system (ARMOS) method and serum CEA test by Elecsyschemiluminescence immunoassay system at the time of diagnosis from January 2010to October 2011. The correlation of EGFR mutation status with patientcharacteristics, maximal standard uptake value (SUVmax) of primary tumorsand metastatic lymph nodes and the serum CEA level were analyzed.Receiver-operating characteristic (ROC) curve analysis was performedto quantify the predictive value of these factors. Multivariate logisticregression analysis was used to analyze predictors of EGFR mutations. Survivalwas evaluated according to SUVmax and EGFR mutation status. 

Result: EGFRmutations were identified in 167 patients (73 EGFR mutation and 94 wild-type). The[18F]-FDG uptake was significantly lower in EGFR mutation than wild-typeNSCLC patients in primary lesion and metastatic lymph nodes (P<0.05).The CEA value was significantly higher in EGFR-mutation (median CEA 12.50ng/mL)than wild-type (5.80ng/mL) NSCLC patients (P=0.030). The ROC analysisconcluded that high FDG uptake (SUV>9.60) may be predictive of the wild-typeEGFR genotype, whereas a lownormalized SUVmax may predict the presence of EGFRmutations. We also demonstrated that high CEA levels (CEA>9.25ng/ml) werepositively correlated with histological EGFR gene mutations by ROCanalysis. On multivariate analysis, never-smoker, low SUVmax of the primarytumor, metastatic lymph nodes, and high CEA value were significantly associatedwith EGFR mutation status. In addition, we also showed that the EGFR exon19 mutation is strongly correlated with higher SUVmax than L858R mutation (P=0.022).We also found that patients with EGFR mutations had longer OS thanthose with EGFR wild-type. 

Conclusion: In conclusion, this studysuggests that in advanced NSCLC patients in general, Chinese patients inparticular, a lower SUVmax on [18F]-PET and a higher CEA are correlated with EGFRmutations and may serve as predictors for the responsiveness to EGFRTKItherapy.

Key Words: NSCLC  EGFR-TKI serum CEA