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

Background: 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.

Methods: 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.

Results: 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%).

Conclusions: EOLA patients exhibited distinct clinical and genetic characteristics compared with LOLA patients.