Lung cancer in young individuals; risk factors and epidemiology

Lung cancer remains a leading cause of cancer-related deaths globally, with an estimated 2.5 million new patients and 1.8 million deaths in 2022. While lung cancer predominantly affects older individuals, there is growing concern about the impact of lung cancer on younger generations, specifically adolescents and young adults (AYA) patients aged 15-39 years. Lung cancer in young individuals has several unique characteristics, such as sex preference, histological subtype, and frequency of somatic mutations in EGFR, ALK, and ROS1. In this article, we describe the risk factors for young patients with lung cancer in two aspects: internal and external predispositions. Although many researchers have focused on genetic predispositions, such as germline genetic alterations, genetic predispositions cannot fully explain the development of lung cancer in young patients. Therefore, we focused on external factors, such as viral infections. Younger patients generally have a better prognosis than older patients, and there is minimal difference in survival rates among advanced-stage young and older patients, which indicates the importance of early detection and intervention, regardless of age. The younger generation has fewer opportunities for radiography or computed tomography, and accidental detection during the examination of other diseases is extremely valuable and effective. Awareness-building activities for pediatricians and other specialists, such as general internal medicine specialists, are important for improving the outcomes of young patients with lung cancer.