Value of F-FDG PET/CT for Predicting EGFR Mutations and Positive ALK Expression in Patients with Non-small Cell Lung Cancer: a Retrospective Analysis of 849 Chinese Patients

Purpose: Epidermal growth factor receptor (EGFR) mutations and the anaplastic lymphoma kinase (ALK) rearrangement are the two most common druggable targets in non-small cell lung cancer (NSCLC). However, genetic testing is sometimes unavailable. Previous studies regarding the predictive role of F-FDG PET/CT for EGFR mutations in NSCLC patients are conflicting. We investigated whether or not F-FDG PET could be a valuable noninvasive method to predict EGFR mutations and ALK positivity in NSCLC using the largest patient cohort to date.

Methods: We retrospectively reviewed and included 849 NSCLC patients who were tested for EGFR mutations or ALK status and subjected to F-FDG PET/CT prior to treatment. The differences in several clinical characteristics and three parameters based on F-FDG PET/CT, including the maximal standard uptake value (SUV) of the primary tumor (pSUV), lymph node (nSUV) and distant metastasis (mSUV), between the different subgroups were analyzed. Multivariate logistic regression analysis was performed to identify predictors of EGFR mutations and ALK positivity.

Results: EGFR mutations were identified in 371 patients (45.9%). EGFR mutations were found more frequently in females, non-smokers, adenocarcinomas and stage I disease. Low pSUV, nSUV and mSUV were significantly associated with EGFR mutations. Multivariate analysis demonstrated that pSUV < 7.0, female sex, non-smoker status and adenocarcinoma were predictors of EGFR mutations. The receiver operating characteristic (ROC) curve yielded area under the curve (AUC) values of 0.557 and 0.697 for low pSUV alone and the combination of the four factors, respectively. ALK-positive patients tended to have a high nSUV. Younger age and distant metastasis were the only two independent predictors of ALK positivity.

Conclusion: We demonstrated that low pSUVmax is associated with mutant EGFR status and could be integrated with other clinical factors to enhance the discriminability on the EGFR mutation status in some NSCLC patients whose EGFR testing is unavailable.