Lung Cancer in Nonsmokers: Causes, Risk Factors, and Outlook

Learn why lung cancer occurs in nonsmokers, explore risk factors, survival rates, and tailored treatment options for better outcomes.

By Sneha Tete, Integrated MA, Certified Relationship Coach

Created on Sep 26, 2025

Learn why lung cancer occurs in nonsmokers, explore risk factors, survival rates, and tailored treatment options for better outcomes.

Lung cancer is widely associated with tobacco use, yet a significant number of people diagnosed with lung cancer have never smoked. This article examines why lung cancer occurs in nonsmokers, explores potential risk factors, reviews survival statistics, and describes the treatment approaches for these individuals.

Why Can Nonsmokers Get Lung Cancer?
How Common is Lung Cancer Among Nonsmokers?
Main Risk Factors for Lung Cancer in Nonsmokers
Types of Lung Cancer Diagnosed in Nonsmokers
Diagnosis Challenges in Nonsmokers
Survival Rates and Prognosis
How is Lung Cancer Treated in Nonsmokers?
Prevention Strategies and Screening
Frequently Asked Questions (FAQs)

Why Can Nonsmokers Get Lung Cancer?

Although smoking is a well-known cause of lung cancer, not all cases are related to tobacco use. Nonsmokers can develop lung cancer due to a combination of genetic, biological, and environmental factors. Scientists believe many causes remain to be discovered, but the following mechanisms play important roles:

Genetic factors: Some individuals inherit mutations that increase their risk of certain lung cancers, irrespective of smoking history.
Environmental exposures: Carcinogens such as radon, asbestos, air pollution, and secondhand smoke can damage lung tissue and initiate cancer growth.
Pre-existing lung disease: Chronic inflammation or scarring from infections or diseases (like tuberculosis) may increase susceptibility.
Hormonal factors and viruses: Especially relevant in certain populations, such as nonsmoking women, where hormones or viral infections may contribute to risk.

Many cases of lung cancer in nonsmokers lack a clear, direct cause. Research continues to uncover new genetic alterations and unidentified environmental risks that could explain why some nonsmokers develop the disease.

How Common is Lung Cancer Among Nonsmokers?

Population studies report that about 10% of all new lung cancer diagnoses occur in people who have never smoked. This figure may slightly fluctuate based on region, gender, and access to diagnostic services. Research has also found that lung cancer in nonsmokers is the most common type of cancer in this group, and it is especially prevalent among women. In fact, globally, up to two-thirds of lung cancer cases in nonsmokers occur in females.

If lung cancer in never-smokers were considered separately, it would be among the leading causes of cancer death in the United States. Estimates suggest that more than 20,000 Americans who never smoked die from lung cancer each year.

Main Risk Factors for Lung Cancer in Nonsmokers

Lung cancer risk in nonsmokers stems from several environmental, biological, and occupational factors. The following table summarizes the leading identified risks:

Risk Factor	Description	Notes
Secondhand smoke	Breathed in from others’ cigarettes, cigars, or pipes	Proven risk, increases likelihood of lung cancer significantly
Radon exposure	A radioactive gas found in homes/buildings, especially basements	Second-leading cause after active smoking
Occupational hazards	Exposure to asbestos, arsenic, diesel fumes, or other chemicals	Risk depends on exposure level and duration
Air pollution	Outdoor (vehicle/plants) and indoor (smoke from wood/cooking)	Linked to increased incidence, especially in urban areas
Genetic mutations	Inheritable DNA changes or acquired gene alterations in the lung	Such as EGFR, ALK, ROS1 mutations, especially in non-smoking lung cancers
Pre-existing lung diseases	History of tuberculosis, chronic bronchitis, or lung scarring	Chronic inflammation may predispose lung tissue to malignancy
Hormonal factors & viruses	Some cancers may be influenced by estrogen or viral infections	Proposed in studies on non-smoking females; ongoing research

It’s important to note that in a large proportion of cases, no obvious environmental or genetic risk can be identified. This underscores the need for ongoing epidemiological and genetic research.

Types of Lung Cancer Diagnosed in Nonsmokers

There are two main categories of lung cancer:

Non-small cell lung cancer (NSCLC): The most frequent type in both smokers and nonsmokers, accounting for about 85% of lung cancer cases overall. In nonsmokers, NSCLC is overwhelmingly dominant.
Small cell lung cancer (SCLC): Less common, more strongly associated with heavy smoking.

Of the NSCLC subtypes, adenocarcinoma is the most common type found in people who have never smoked. It develops from epithelial cells that line the lungs and is often found in the outer regions of the lungs. Other NSCLC subtypes include squamous cell carcinoma and large cell carcinoma, but these are less frequent in nonsmokers.

Diagnosis Challenges in Nonsmokers

Lung cancer in nonsmokers often presents unique diagnostic difficulties:

Delayed suspicion: Health providers and patients may not initially consider lung cancer when there’s no history of smoking, leading to delays in diagnosis.
Non-specific symptoms: Symptoms such as persistent cough, chest pain, mild shortness of breath, or fatigue may be attributed to common infections or allergies rather than cancer.
Advanced stage at diagnosis: Many nonsmokers are diagnosed at later stages, when symptoms become more severe or the disease has already spread.

Common symptoms of lung cancer include:

Chronic cough (that does not improve over weeks)
Shortness of breath
Chest pain or discomfort
Unexplained weight loss
Coughing up blood
Persistent hoarseness

If you experience any of these symptoms, especially with known risk factors or family history, it is critical to seek medical evaluation promptly.

Survival Rates and Prognosis for Nonsmokers

Prognosis for nonsmokers with lung cancer may be different, and often more favorable, than for smokers due to several factors:

Improved survival rates: According to the American Cancer Society, the overall 5-year relative survival rate for NSCLC ranges from 28% to 65%, depending mostly on the stage at diagnosis.
Nonsmokers fare better: Several recent studies confirm that nonsmokers have a ~20% lower risk of death after a lung cancer diagnosis compared to smokers. This may be due to younger age at diagnosis, fewer additional health problems, and better responses to certain therapies.
Genetically-targeted therapies: Cancers in nonsmokers are more likely to have treatable genetic mutations—making them suitable for precision therapy, which can yield better outcomes.

However, outcomes also depend strongly on the stage at which the cancer is found, the exact genetic mutations present, overall health at diagnosis, and access to care.

How is Lung Cancer Treated in Nonsmokers?

Treatment for nonsmoking lung cancer patients is tailored to the tumor type, genetic profile, and stage of disease. Notably, NSCLC in nonsmokers often involves gene mutations that make them especially responsive to targeted medications. Treatment options include:

Surgery: For early-stage cancers, surgical removal offers the best chance for cure.
Targeted therapies: Many nonsmokers with NSCLC have gene alterations such as EGFR, ALK, or ROS1. Approved drugs called tyrosine kinase inhibitors (e.g., osimertinib, erlotinib, crizotinib) can block these drivers of cancer growth with fewer side effects than traditional chemotherapy.
Chemotherapy: May be used alone or with other treatments, especially in the absence of actionable mutations.
Immunotherapy: Checkpoint inhibitors may help the body’s own immune system identify and destroy cancer cells.
Radiation therapy: Used to control symptoms or as part of curative therapy for specific cases.

Nonsmokers with lung cancer typically have fewer comorbid conditions such as chronic obstructive pulmonary disease (COPD) or heart disease, improving their ability to tolerate aggressive treatment. Additionally, lifestyle counseling focuses largely on healthy recovery and lowering exposure to future lung hazards rather than cessation of tobacco use.

Prevention Strategies and Screening

While some risk factors (such as genetics) are beyond control, there are important steps to help reduce the risk of lung cancer in nonsmokers:

Avoid secondhand smoke: Reduce exposure at home, work, and in social settings.
Test for radon: Use available kits to measure levels at home, especially in high-risk areas.
Improve indoor air quality: Use venting when cooking and heating; avoid burning materials indoors without proper ventilation.
Protect against workplace hazards: Use personal protective equipment if you work with known carcinogens and follow occupational safety guidelines.
Maintain general lung health: Exercise regularly and seek prompt treatment for lung infections or diseases.

Currently, systematic lung cancer screening (typically a low-dose CT scan) is recommended only for people who meet certain age and smoking history criteria. There are currently no consensus guidelines for screening nonsmokers. This is because the risks and benefits haven’t yet favored broad screening, given the lower—but not negligible—rate of lung cancer in this group. However, if you have additional risk factors (such as strong family history or high radon exposure), discuss individualized screening options with your healthcare provider.

Frequently Asked Questions (FAQs)

Q: Can you get lung cancer even if you never smoked?

A: Yes, up to 10% of lung cancer cases occur in people who have never smoked. These cases can result from genetic factors, environmental exposures (such as radon or secondhand smoke), or, in many cases, an unknown cause.

Q: Are outcomes better for nonsmokers with lung cancer?

A: Survival rates for nonsmokers with lung cancer are generally better than those for smokers, especially when the disease is caught early and is linked to treatable gene mutations. Nonsmokers often have fewer additional medical conditions, which also improves treatment tolerance and overall outcomes.

Q: What symptoms should nonsmokers look out for?

A: Warning signs include a persistent cough, chest pain, shortness of breath, unexplained weight loss, or coughing up blood. Since nonsmokers’ symptoms are often mistaken for other illnesses, persistent changes should always prompt medical review.

Q: If I am a nonsmoker, should I be screened for lung cancer?

A: Universal screening for nonsmokers is not currently recommended due to the low overall incidence. However, if you have risk factors such as strong family history or substantial environmental exposure, discuss the potential benefits and risks of screening with your doctor.

Q: What can I do to lower my risk of lung cancer as a nonsmoker?

A: Reducing secondhand smoke exposure, testing your home for radon, minimizing workplace chemical exposure, and generally maintaining lung health are key steps. While not all cases are preventable, these actions can lower your overall risk.

References

Author

Sneha TeteBeauty & Lifestyle Writer

Sneha is a relationships and lifestyle writer with a strong foundation in applied linguistics and certified training in relationship coaching. She brings over five years of writing experience to thebridalbox, crafting thoughtful, research-driven content that empowers readers to build healthier relationships, boost emotional well-being, and embrace holistic living.

Read full bio of Sneha Tete