From the Guidelines
Lung adenocarcinoma is the most common type of lung cancer not linked to smoking, and it often develops in the outer regions of the lungs. This type of cancer, along with others such as bronchioloalveolar carcinoma, carcinoid tumors, and some cases of large cell carcinoma, can occur in non-smokers 1. The causes of these cancers in non-smokers may include genetic factors, with mutations in genes like EGFR, ALK, and ROS1 being more common in non-smokers 1. Environmental factors also play a role, including exposure to radon gas, secondhand smoke, air pollution, asbestos, and other workplace carcinogens. Some lung cancers in non-smokers may be associated with prior lung diseases or infections.
Key points to consider include:
- Women and East Asian populations have higher rates of non-smoking related lung cancers 1
- Understanding the distinctions between smoking and non-smoking related lung cancers is important because they often respond differently to targeted therapies that address specific genetic mutations 1
- The goal of lung cancer screening is to detect early-stage disease before it becomes clinically evident and when appropriate treatment can lead to improved survival 1
It's essential to note that while smoking is a major cause of lung cancer, a significant proportion of lung cancer cases occur in non-smokers, with approximately 500,000 deaths annually attributed to lung cancer in lifetime never-smokers 1. Therefore, it is crucial to consider non-smoking related lung cancers in the diagnosis and treatment of lung cancer, regardless of the patient's smoking history.
From the Research
Types of Lung Cancer Not Caused by Smoking
- Non-small cell lung cancer (NSCLC) in non-smokers is considered a biologically unique type of lung cancer, with risk factors and tumorigenic conditions other than tobacco smoke 2
- Adenocarcinoma is the most common histological type in non-smokers, while squamous cell carcinoma is more commonly associated with smoking 3
- Lung cancers with EGFR mutations and ALK&ROS1 fusions are more common in non-smokers, particularly in females and those with adenocarcinoma 4
Characteristics of Non-Smoking-Associated Lung Cancer
- Non-smoking-associated lung cancer tends to have distinct driver genes and genetic pathway alterations 2
- Non-smokers with lung cancer are more likely to have adenocarcinoma, and are less likely to have emphysema 5, 4
- Non-smokers with lung cancer may have a better prognosis than smokers, with a median survival of 6.6 years compared to 3.9 years for smokers 5
Risk Factors for Non-Smoking-Associated Lung Cancer
- Radon exposure and air pollution are known risk factors for lung cancer, in addition to tobacco smoke 6
- Lifestyle-related risk factors, other than tobacco smoke, may play a role in the development of lung cancer in non-smokers 2
- Genetic predisposition, such as hereditary cancer syndromes, may also contribute to the development of lung cancer in non-smokers 2