From the Guidelines

Tobacco smoking is the primary cause of bronchogenic carcinoma (lung cancer).

The development of lung cancer is a complex process involving multiple factors, including:

Tobacco smoking: the main cause of lung cancer, responsible for 71% of lung cancer deaths globally 1
Genetic and epigenetic factors: inter-individual differences in susceptibility play an important role in lung carcinogenesis 1
Occupational exposures: to agents such as asbestos, arsenic, radon, and non-tobacco-related polycyclic aromatic hydrocarbons 1
Air pollution: indoor and outdoor air pollution, including exposure to diesel exhaust and secondhand tobacco smoke 1
Acquired lung disease: underlying lung disease, such as chronic obstructive pulmonary disease (COPD) and pneumoconiosis, may increase susceptibility to lung cancer 1
Family history: a positive family history is a clinically useful risk indicator for lung cancer 1 Key factors that contribute to the development of lung cancer include:
DNA damage and mutations: induced by cigarette smoke carcinogens and other environmental factors 1
Field carcinogenesis: the process by which normal cells in the airway epithelium are transformed into cancer cells 1
Preneoplasia: the presence of precancerous lesions in the airway epithelium 1 It is essential to note that while tobacco smoking is the primary cause of lung cancer, other factors can also contribute to the development of the disease. Therefore, a comprehensive approach to prevention and early detection is crucial for reducing the incidence and mortality of lung cancer.

From the Research

The causes of bronchogenic carcinoma (lung cancer) can be attributed to various factors, including:

Occupational and environmental carcinogens, such as asbestos, radon daughters, diesel exhaust, and metals 2
Tobacco smoking, which causes approximately 85-90% of bronchogenic carcinoma 3, 4
Environmental tobacco exposure or second-hand smoke, which may cause lung cancer in life-long non-smokers 3
Certain occupational agents, such as arsenic, chromium, nickel, and vinyl chloride, which increase the relative risk for lung cancer 3
Familial predisposition, which is an area of advancing research 3
Dietary factors, with vitamins A, C, and E proposed as having a protective effect 3

The risk factors for bronchogenic carcinoma include:

Exposure to tobacco smoke, ionizing radiation, and chloromethyl ethers, which pose a substantially greater risk for development of small cell lung cancer (SCLC) 5
Additive or multiplicative effect of smoking with certain occupational agents, such as asbestos and radon daughters 2, 3
Genetic alterations, including the activation of dominant proto-oncogenes and the inactivation of tumor suppressor genes, which have been described in SCLC 5

The epidemiology of lung cancer is characterized by:

High incidence and mortality rates, with lung cancer being the leading cause of cancer death in the United States 3, 4
Slow decline of smoking in the United States, which will likely continue to contribute to the devastation of lung cancer for years to come 3
Importance of early detection and localization of lung cancer to improve overall survival 6