The correlation of mutation status of EGFR and KRAS with SUVmax of 18F-FDG-PET/CT in non-small-cell lung-cancer

Objectives: Epidermal growth factor receptor (EGFR) mutation predicts benefit from EGFR-tyrosine kinase inhibitor (EGFR-TKIs) treatment, and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation is a weak, but valid predictor for poor prognosis as well as treatment outcomes in non-small cell lung cancer (NSCLC). The present study aimed to investigate if the maximum standardized uptake value (SUVmax) derived from 18F‑FDG PET‑CT can be used to predict the mutation status of EGFR and KRAS in NSCLC patients.

Methods: We retrospectively studied 164 primary lung cancer patients(105 males and 59 females )who underwent FDG PET/CT imaging before any treatment,also EGFR mutations were detected by direct sequencing in the pathology department. Continuous covariates were analyzed using Mann-Whitney Test. Univariate and Multivariate logistic regression analysis to evaluate the correlation of EGFR mutation, KRAS mutation and SUVmax was performed with established clinical factors of age and gender.

Results: EGFR and KRAS mutations were detected in 162 (30.86%) and 62 (14.52%) of the 164 NSCLC patients, respectively. In our cases, 50 patients (30.86%, 33 females and 17males) have mutational EGFR (group 1), 112 patients (69.14%, 24 females and 88 males) were wild EGFR (group 2). Multivariate analysis showed the gender of female was the most significant factor (p < 0.001) for the EGFR mutations in NSCLC. And the tumor matabolism metric SUVmax was predictive for the EGFR mutations in NSCLC in a univariate analysis.The median (M) of SUVmax was significantly lower in group 1 (M: 7.5) than in group 2 (M:10.725)( P < 0.001). However, no relationship was noted between KRAS mutation status and SUVmax. Conclusion: EGFR mutation-type NSCLCs have relatively lower SUVmax compared with NSCLCs without EGFR mutation. Besides, the EGFR mutations were higher in female patients than males(55.93% vs. 16.19%, P < 0.001). The study demonstrated that gender and lower level of SUVmax are of great importance about EGFR mutation in NSCLC. Also, there is no relationship between KRAS mutation status and SUVmax was observed in this study. Keywords: EGFR mutation; KRAS mutation; SUVmax