Clinicopathological Characteristics, Molecular Findings, and Survival of Lung Cancer in Adults Aged <30 Years in China: A Retrospective Cohort Study

Background/Objectives: Lung cancer is increasingly recognized in young adults, but data specific to patients younger than 30 years remain scarce. We aimed to characterise the clinicopathological features, molecular profiles, and survival outcomes of lung cancer in adults younger than 30 years. Methods: A retrospective cohort study was conducted at the Department of Respiratory Disease, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China. Patients aged 18 to 30 years with pathologically confirmed primary lung cancer, admitted between August 2011 and October 2021, were identified from the pathology and oncology databases of the study centre; eligibility and exclusion criteria and the resulting analytic cohort are summarized below (a screened/excluded patient count could not be reconstructed retrospectively; see Limitations). Demographics, histology, stage (eighth-edition TNM), driver mutations, and treatment were extracted, and the extent of missing data for each variable was assessed. Molecular testing was not performed prospectively for this study; rather, we report driver-mutation results that had already been generated as part of routine clinical care for patients in whom testing was clinically indicated and archived tissue was available. Overall survival (OS) was estimated using the Kaplan–Meier method and compared using the log-rank test; hazard ratios (HRs) were derived from univariate Cox regression and are reported as exploratory/descriptive given the non-randomized comparison (see Discussion). Results: Among 139 patients meeting eligibility criteria, the cohort was predominantly female (65.5%) and most individuals were never-smokers (92.8%), with adenocarcinoma predominating (93.5%). Stage I (61.2%) and stage IV (30.2%) were most common. Of 34 patients (24.5%) with available molecular testing results, 23 (67.6%) carried a driver mutation, of whom 19 (82.6%) had stage IV disease. Among mutation-positive patients—drawn from a selectively tested subcohort enriched for advanced-stage disease—ALK rearrangement was most frequent (13; 56.5%). In the stage IV subgroup, patients who received first-line tyrosine kinase inhibitors (TKIs) had a longer observed OS than those who did not (median, 88 vs. 24 months); this exploratory, non-randomized comparison is reported descriptively rather than as an adjusted treatment-effect estimate (see Limitations). Conclusions: In this single-centre retrospective cohort, adults aged <30 years with lung cancer were predominantly female never-smokers with adenocarcinoma. Among the selectively tested advanced-stage subgroup, ALK fusions were common. These data justify further multicentre study and broader contemporary molecular characterisation.