EGFR Mutation Rates Correlate with Age at Diagnosis and Tumor Characteristics in Patients with Pulmonary Ground-Glass Opacities.

Background: To clearly reveal the correlations between tumor characteristics, age at diagnosis, and epidermal growth factor receptor (EGFR) mutation rates in patients with pulmonary ground-glass opacities (GGOs).

Methods: We retrospectively reviewed 1473 patients with GGOs between January 2015 and May 2020 from two cancer centers. The tumor characteristics and EGFR mutation rates were compared between different age groups. Multivariate logistic regression was fitted to analyze the relationship between age, tumor characteristics, and EGFR mutation rates.

Results: The older patients had more large tumors, mixed GGOs with a consolidation-to-tumor ratio (CTR) of >0.5, and invasive adenocarcinoma (IAC) and pathologic stage IA2-IB. Overall, the rate of EGFR mutations in GGOs was 57.3% and the main subtypes were L858R and 19del mutations. The distribution of EGFR subtypes varied in different age and GGO diameter groups. Age (p = 0.036), GGO types (p = 0.005), tumor diameter (p = 0.039), and pathological types (p < 0.001) were significant predictors for EGFR mutation status. Importantly, significant differences in EGFR mutation rates between age groups were mainly observed in the GGO ≤2 cm diameter (p < 0.001), pure GGOs (p = 0.001), and IAC (p = 0.039) cohorts. Overall, those diagnosed at >50 years of age had a 47.0% increased likelihood of harboring EGFR mutations. Compared with the older group, the increased chance of harboring EGFR mutations for patients with larger tumors, mixed GGOs, and IAC was greater in the younger group.

Conclusions: The EGFR mutation rates were varied among different tumor characteristics and age at diagnosis. These findings provide new insights into the treatment of GGOs.