Non-smokers and lung cancer: Understanding causes, symptoms, treatments, and additional information
In the United States, a significant proportion of lung cancer cases are now being diagnosed in people who have never smoked. Adenocarcinoma, a subtype of non-small cell lung cancer (NSCLC), is particularly common among this group, accounting for up to 20% of all lung cancer cases[1][2].
This trend is most noticeable among women and individuals of Asian ancestry, with the relative share of lung cancer diagnoses in never-smokers increasing despite a decline in national smoking rates[1][2].
Several factors contribute to the rise of adenocarcinoma among never-smokers. These include genetic predisposition, environmental exposures, improvements in detection, and inflammation linked to lifestyle factors.
- Genetic Predisposition: Approximately 8% of lung cancers may be inherited or linked to genetic factors, predisposing individuals to cancer despite their lack of smoking history[1][2].
- Environmental Exposures: Ambient air pollution, secondhand smoke, and occupational hazards such as radon, asbestos, diesel exhaust, and thoracic radiation increase the risk among never-smokers[2][4].
- Improvements in Detection: The increased use of imaging technologies like CT scans has improved early tumor detection, which partly explains the apparent rise in diagnosed cases among never-smokers[1][2][4].
- Inflammation and Lifestyle Factors: Lung inflammation, potentially linked to environmental and lifestyle factors beyond smoking, may contribute to the cancer risk in never-smokers[1][2].
It's important to note that nonsmokers with lung cancer do not respond better to treatment or have a better outlook than those who smoke. Symptoms of lung cancer can include frequent coughing, coughing up blood, chest pain, shortness of breath, and wheezing.
If lung cancer is suspected, diagnosis typically begins with a physical exam and medical history, followed by imaging tests such as chest X-ray, CT scan, MRI, PET scan, bone scan, ultrasound, and cell examination from sputum, fluid around the lungs, or biopsy of a mass. Doctors may further analyze cancer cells to see if they have genetic changes that would make them viable candidates for targeted therapies.
Currently, there are no guidelines that recommend lung cancer screening in those who do not smoke. However, talking to an employer about limiting exposure to cancer-causing substances in the workplace can help reduce the risk of developing lung cancer.
One significant risk factor for lung cancer among never-smokers is radon, a radioactive gas that comes from the breakdown of uranium in rocks and soils. Radon tests can help reduce the risk of developing lung cancer. In fact, the primary cause of lung cancer among people who have never smoked is radon[3].
Approximately 10-20% of lung cancers in the United States each year occur in people who smoked fewer than 100 cigarettes in their lifetime or never smoked at all[5]. Avoiding public areas where smoking is allowed and not permitting smoking in the home or car can help reduce exposure to secondhand smoke, another risk factor for lung cancer.
[1] American Cancer Society. (2021). What Are the Key Statistics About Lung Cancer? [2] Mayo Clinic. (2021). Lung Cancer: Symptoms and Causes. [3] National Cancer Institute. (2019). Radon and Lung Cancer Risk. [4] American Lung Association. (2021). Radon: The Second Leading Cause of Lung Cancer. [5] Centers for Disease Control and Prevention. (2021). Data & Statistics About Tobacco Use and Tobacco Control.
- The apparently rising number of non-small cell lung cancer (NSCLC) cases among never-smokers may be due to genetic predisposition, as up to 8% of lung cancers are believed to be inherited or linked to genetic factors [1][2].
- Ambient air pollution, secondhand smoke, and occupational hazards such as radon, asbestos, diesel exhaust, and thoracic radiation increase the risk of lung cancer among never-smokers, contributing to the rise of adenocarcinoma in this group [2][4].
- Improved detection methods, including the increased use of CT scans, have played a role in the apparent rise in diagnosed cases of lung cancer among never-smokers [1][2][4].
- Inflammation and lifestyle factors beyond smoking may contribute to the cancer risk in never-smokers, which could partially explain the trend observed in this population [1][2].
