Lung cancer in patients who have never smoked — an emerging disease

Lung cancer is the most common cause of cancer-related deaths globally. Although smoking-related lung cancers continue to account for the majority of diagnoses, smoking rates have been decreasing for several decades. Lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths worldwide in 2023, preferentially occurring in women and Asian populations. As smoking rates continue to decline, understanding the aetiology and features of this disease, which necessitate unique diagnostic and treatment paradigms, will be imperative. New data have provided important insights into the molecular and genomic characteristics of LCINS, which are distinct from those of smoking-associated lung cancers and directly affect treatment decisions and outcomes. Herein, we review the emerging data regarding the aetiology and features of LCINS, particularly the genetic and environmental underpinnings of this disease as well as their implications for treatment. In addition, we outline the unique diagnostic and therapeutic paradigms of LCINS and discuss future directions in identifying individuals at high risk of this disease for potential screening efforts. Lung cancer is a disease typically associated with tobacco smoking; however, lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths globally. Moreover, smoking rates are declining around the world and therefore LCINS is likely to increase as a proportion of all lung cancers over time. Thus, understanding the aetiology and features of LCINS is increasingly important. Herein, the authors review the emerging data on the epidemiology, clinical characteristics and molecular features of LCINS as well as the genetic and environmental risk factors for this disease. They also summarize the unique diagnostic and management paradigms of LCINS.