Age-related differences in clinical characteristics and survival in lung cancer.

BACKGROUND: Lung cancer predominantly affects older adults; however, an increasing number of cases are diagnosed in younger patients. Age-related differences in baseline characteristics, survival outcomes, and prognostic factors remain incompletely understood. This study aimed to compare clinical features, laboratory profiles, and survival outcomes between young and elderly patients with lung cancer and to identify prognostic factors associated with overall survival (OS) and progression-free survival (PFS). METHODS: This retrospective cohort study screened patients with pathologically confirmed primary lung cancer diagnosed in 2022. Patients aged ≤45 years were classified as the young group, and those aged ≥75 years as the elderly group. Baseline demographic characteristics, laboratory parameters, and nutritional-inflammatory indices were compared between groups. Survival outcomes were evaluated using Kaplan-Meier analyses and compared with the log-rank test. Univariate and multivariate Cox proportional-hazards regression analyses were performed to identify prognostic factors for OS and PFS. RESULTS: A total of 44 patients were included (21 young, 23 elderly). Elderly patients had higher smoking exposure and worse nutritional and inflammatory profiles, including lower albumin and prognostic nutritional index values. Younger patients showed significantly longer OS, while PFS was numerically longer but not statistically significant despite a tendency toward more advanced disease. In univariate analyses, histology type, gene mutation status, and treatment modality were associated with survival outcomes. In the simplified multivariable Cox models, immunotherapy was independently associated with improved OS, and targeted therapy, surgery, and immunotherapy were associated with better PFS. CONCLUSIONS: Young and elderly patients with lung cancer exhibit distinct clinical, laboratory, and survival profiles. Younger patients demonstrated more favorable genomic profiles and survival outcomes. These findings highlight the importance of age-specific evaluation and suggest that treatment-related and host-related factors should be considered in prognostic assessment.