Non-Smokers and Lung Cancer
Understanding what lung cancer is and Learning about its risk factors and its clinical implications, symptoms, diagnosis, treatment and prevention strategies.
Written by Dr.Sonia Bhatt
Last updated on 3rd Jul, 2025
Lung cancer is the foremost cause of cancer-related mortality globally, leading to about 1.8 million deaths annually. Although tobacco smoking is the main risk factor, roughly 20% of lung cancer fatalities occur in individuals without a smoking history, as reported by the American Cancer Society.
Aside from smoking, other notable risk factors include exposure to second-hand smoke, radon gas, air pollution, a familial history of lung cancer, and asbestos exposure. This complexity in the causes of lung cancer highlights the importance of increased awareness and preventive strategies that extend beyond simply quitting smoking.
Causes of Lung Cancer in Non-Smokers
Lung cancer in non-smokers often results from a combination of factors rather than a single cause. A key factor can be the presence of genetic mutations in the tumour, referred to as somatic mutations, which can contribute to cancer development. This differs from germline mutations, which exist in all normal DNA. Research has shown that somatic mutations or abnormalities can significantly influence the development of lung cancer, especially in those who have never smoked.
Several environmental risk factors may lead to lung cancer in non-smokers:
Radon Gas: Radon exposure is a significant cause of lung cancer among non-smokers. Radon is an invisible and odourless gas that occurs naturally outdoors but can accumulate indoors in homes situated on soil with uranium deposits.
Second-hand Smoke: This is the smoke inhaled from someone else’s tobacco product and is linked to lung cancer deaths annually worldwide. Researchers are also studying "third-hand smoke," which refers to the residual nicotine and chemicals that may remain on surfaces like furniture, walls, and clothing.
Occupational Carcinogens: Long-term exposure to cancer-causing substances, such as asbestos, heavy metals, and diesel exhaust, poses a serious risk for individuals in certain professions.
Air Pollution: Both indoor and outdoor air pollution have been associated with lung cancer.
Risk Factors for Non-Smokers
While smoking is the primary cause of lung cancer, various other risk factors can contribute to the disease in non-smokers. These include a family history of lung cancer and environmental influences and occupational hazards like asbestos and diesel exhaust.
Some individuals may develop lung cancer without any known risk factors, potentially due to random biological events or unidentified causes. Lung cancers in non-smokers often differ from those in smokers. They tend to occur in younger individuals and exhibit specific genetic changes that can inform treatment decisions. Additionally, chronic lung conditions, such as chronic obstructive pulmonary disease (COPD), may also contribute to an increased risk of lung cancer.
Symptoms of Lung Cancer
Symptoms of lung cancer can include:
A persistent cough that worsens over time
Chest pain
Shortness of breath
Wheezing
Coughing up blood
Ongoing fatigue
Unexplained weight loss
Other changes that may occur with lung cancer include frequent bouts of pneumonia and swollen or enlarged lymph nodes in the chest area between the lungs.
These symptoms can affect both smokers and non-smokers alike. Some people may feel generally unwell or fatigued, while others might experience a constant cough, chest pain, wheezing, or breathing difficulties.
Diagnosis of Lung Cancer in Non-Smokers
Lung cancer often shows no symptoms in its early stages, which is why routine screenings for non-smokers and never-smokers are typically not performed. Most cases of early-stage lung cancer in non-smokers are discovered incidentally during X-rays or CT scans conducted for other medical reasons.
Family history is a significant factor to consider. Individuals worried about a potential history of lung cancer—especially if a first-degree relative or multiple family members have been diagnosed, or if a family member was diagnosed at a young age—should discuss these concerns with their healthcare provider. It's also important to mention any exposure to second-hand smoke, radon, industrial pollution, or other known risk factors.
Low-dose computed tomography (LDCT) is a vital tool in lung cancer screening. These scans can identify small nodules or abnormalities in the lungs, facilitating early diagnosis and treatment. Non-smokers with a family history or other risk factors may benefit from regular LDCT screenings as part of a proactive health approach.
Additionally, biomarker testing is an emerging method for early detection. By examining blood samples, healthcare providers can identify specific proteins or genetic mutations linked to lung cancer. This non-invasive technique has the potential to identify high-risk individuals and tailor treatment strategies accordingly.
Treatment Options for Non-Smoking Lung Cancer Patients
Non-smokers with lung cancer are typically treated similarly to smokers. Common treatment methods for lung cancer include:
Surgery
Immunotherapy
Chemotherapy
Radiation therapy
Targeted therapy
Lung cancers in non-smokers often differ from those in smokers. The most common type found in non-smokers is adenocarcinoma, which usually originates in the mucus-producing cells of the small airways. Non-smokers tend to be diagnosed at a younger age, and their tumours often display unique genetic changes compared to those in smokers.
The treatment approach for lung cancer in non-smokers often involves a combination of surgery, radiation therapy, chemotherapy, and targeted therapies. Each treatment plan is customised based on the individual’s cancer type, stage, and overall health to achieve the best possible results.
Targeted therapies have significantly changed the landscape of lung cancer treatment, especially for non-smokers with specific genetic mutations. These therapies focus on the defective proteins or pathways that contribute to cancer growth, providing a more tailored and effective treatment option. Drugs aimed at EGFR, ALK, and ROS1 mutations have demonstrated encouraging outcomes in enhancing survival rates and quality of life.
Immunotherapy is another promising avenue for treating lung cancer. By boosting the body's immune response, immunotherapy drugs can enhance the ability to recognise and eliminate cancer cells. This method offers hope for non-smokers with advanced lung cancer, serving as an alternative to conventional treatment options.
Prognosis and Survival Rates
Adenocarcinoma is the most frequently diagnosed lung cancer in non-smokers, typically originating in the outer areas of the lungs, particularly in the mucus-producing cells of the small airways known as bronchioles. This type of cancer has a unique appearance, often presenting as a diffuse haziness rather than a distinct lump.
Cancers in non-smokers tend to grow more slowly. While they are generally less likely to spread (or metastasise) to other parts of the body, there is still a risk of recurrence after successful surgical treatment.
Smokers are more commonly diagnosed with squamous cell carcinoma, a type of non-small cell lung cancer (NSCLC) that accounts for over half of lung cancer cases in smokers. In contrast, the majority of non-smokers are diagnosed with adenocarcinoma, a different form of NSCLC.
Prevention Strategies
Lung cancer can affect both non-smokers and those with a history of smoking. To reduce your risk and that of non-smoking family members, consider these strategies:
No Smoking Indoors: Prohibit smoking in your home and vehicles.
Avoid Smoking Venues: Stay away from public places where smoking is allowed.
Choose Non-Smoking Accommodation: Select non-smoking rooms when travelling or use nicotine detection tests to check for third hand smoke.
Follow Workplace Safety Guidelines: Adhere to health and safety regulations in environments with carcinogen exposure.
Minimise Pollutant Exposure: Avoid second-hand smoke and limit time in polluted areas. Follow safety protocols in industries handling carcinogenic materials.
Taking proactive measures, such as testing for radon and asbestos, can help support lung health. A smoke-free environment is crucial, as avoiding second-hand smoke and advocating for smoke-free spaces protects everyone’s health. Encouraging loved ones to quit smoking contributes to a healthier community.
Conclusion
In summary, lung cancer can affect both smokers and non-smokers alike. Non-smokers are also at risk, making it important to be aware of the associated risk factors. Recognising the symptoms of lung cancer is crucial, as early detection can significantly improve outcomes. By avoiding carcinogens and seeking timely treatment, non-smokers can lower their risk of developing this disease. Ultimately, being informed is essential for promoting good health.
Consult Top Pulmonologist
Consult Top Pulmonologist
Dr Rakesh Bilagi
Pulmonology Respiratory Medicine Specialist
10 Years • MBBS MD PULMONOLOGIST
Bengaluru
Apollo Clinic, JP nagar, Bengaluru
Dr. Aakanksha Chawla Jain
Pulmonology Respiratory Medicine Specialist
9 Years • MD (Pulmonary Medicine), IDCCM, IFCCM (Indian Fellowship in Critical Care Medicine)
Delhi
Apollo Hospitals Indraprastha, Delhi
(250+ Patients)
Dr Ishan Gupta
Pulmonology Respiratory Medicine Specialist
9 Years • MBBS, DNB RESPIRATORY DISEASES
Delhi
Apollo Hospitals Indraprastha, Delhi
(50+ Patients)
Dr Vishwa Vijeth K.
Pulmonology Respiratory Medicine Specialist
8 Years • MBBS, MD ( Respiratory Medicine)
Bangalore
Apollo Clinic Bellandur, Bangalore
Dr. Naseeha Mohammed S V
Pulmonology Respiratory Medicine Specialist
6 Years • MBBS, MD ,DNB Respiratory Medicine
Bengaluru
Apollo Clinic, Sarjapur Road, Bengaluru
.webp)