Metabolic Phenotype of Stage IV Lung Adenocarcinoma Relationship With Epidermal Growth Factor Receptor Mutation

Purpose: Epidermal growth factor receptor (EGFR) mutation status is important in treatment stratification of stage IV lung adenocarcinoma. We evaluated the relationship between the SUVmax measured on PET/CT and EGFR mutations and the value of SUVmax in predicting EGFR mutations. Patients and Methods: Seventy-one stage IV lung adenocarcinoma patients with verified EGFR mutations (48 EGFR mutant, 23 EGFR wild-type) having pretreatment PET/CT were retrospectively reviewed. SUVmax values of the primary tumors (n = 71), nodal (n = 246), and distant metastases (n = 618) were compared between EGFR-mutant and EGFR wild-type adenocarcinoma by Mann-Whitney U test. The receiver operating characteristics curve and logistic regression were performed for factors, SUVmax, age, sex, and smoking status. The significant predictors were assessed individually and in combination in discriminating EGFR mutation status. Statistical significance was assumed at P < 0.05 Results: The metastases in EGFR-mutant adenocarcinoma had lower SUV than EGFR wild-type adenocarcinoma (nodal SUVmax 3.4 vs 5.5, distant metastasis SUVmax 3.4 vs 4.7, respectively; both P < 0.001). No statistical significant difference was observed in the primary tumors SUVmax between the 2 groups (SUVmax 7.4 vs 8.1, P = 0.311). A receiver operating characteristics derived SUVmax less than or equal to 7.2 in metastasis could separate EGFR-mutant from EGFR wild-type adenocarcinoma (area under the curve, 0.71-0.74; P < 0.05). SUVmax was a significant independent predictor, and when combined with age, sex, and smoking status, it is highly predictive of EGFR mutation status (area under the curve, 0.90). Conclusions: Low SUVmax in the metastasis favors the presence of EGFR mutations in stage IV lung adenocarcinoma, and SUVmax is an independent predictor of EGFR mutations.