Clinical and Genetic Characteristics of Early-Onset Lung Adenocarcinoma in a Large Chinese Cohort.

The characteristics of early-onset lung adenocarcinoma (EOLA) have not been extensively studied. Our research aimed to comprehensively assess the clinical and genetic features of EOLA. We conducted a retrospective analysis of surgically resected lung adenocarcinoma patients, categorizing them into the EOLA group (aged <40 years) and the late-onset lung adenocarcinoma (LOLA) group (aged >60 years). A comparative investigation of clinical, germline, and genomic features was conducted. Propensity score matching was used to balance baseline characteristics for gene mutation analysis. We enrolled 487 EOLA and 2507 LOLA patients. EOLA patients exhibited a higher female-to-male ratio (2.55 vs 1.19) and a higher proportion of family history of lung cancer in the ground-grass opacity subgroup (12.7% vs 8.9%). The EOLA group exhibited higher rates of earlier stage in the ground-grass opacity subgroup and solid subgroup. Preinvasive adenocarcinoma was the dominant histologic subtype in the EOLA group within the ground-glass opacity subgroup (73.8% vs 25.6%). After propensity score matching, we analyzed 241 stage 0/I patients with available genetic test results. Significant disparities in gene mutation rates emerged between the EOLA and LOLA patients, including Erb-B2 receptor tyrosine kinase 2 (ERBB2; 38.0% vs 2.8%), epidermal growth factor receptor (EGFR; 36.0% vs 64.5%), MET (0.0% vs 7.1%), neurofibromin 1 (NF1; 0.0% vs. 5.7%), and anaplastic lymphoma kinase (ALK) fusion (10.0% vs 1.4%). EOLA patients exhibited distinct clinical and genetic characteristics compared with LOLA patients.