About 229,000 people in the United States are diagnosed with lung cancer each year. Of those, roughly 20,000 to 40,000, or about 10 to 20 percent, occur in people who never smoked or who smoked fewer than 100 cigarettes in their lifetime. Lung cancer in nonsmokers is not a rounding error. It is roughly the annual diagnosis count of several better-known cancers.
The rise of lung cancer in nonsmokers has been on the rise, but the question is why? And while this question haunts scientists and researchers alike, another question that remains is this: If the increase in lung cancer in nonsmokers is on the rise, how do you detect it before it’s too late?
Understanding Lung Cancer
Whether it’s our heavy panting during a workout or the meditative in and out in an attempt to focus our minds, our every breath is powered by the two spongy organs in our chest – the lungs. Our lungs are responsible for taking in oxygen and expelling carbon dioxide as we exhale.
However, their importance to our everyday lives is not without potential issues.
There are two main types of lung cancer that can impact the daily functions of our lungs: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).
Non-Small Cell Lung Cancer (NSCLC)
NSCLC makes up about 80% to 85% of lung cancers, according to the American Cancer Society. NSCLC consists of three main subtypes: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Of the three, adenocarcinoma is the most common type of lung cancer in those who smoke or used to smoke and those who don’t.
Small Cell Lung Cancer (SCLC)
SCLC accounts for approximately 10% to 15% of all lung cancers and tends to grow and spread rapidly. Often leading to metastatic lung cancer, it usually responds well to chemotherapy and radiation treatment. Despite its positive response to the treatment methods, it often returns at some point in the patient’s life.
What Causes Nonsmoker Lung Cancer?
Recent studies by the United States and the U.K. found that lung cancer is increasing among nonsmokers and never-smokers – but why?
While cigarette smoking remains the greatest risk of developing the disease, many other risk factors can contribute to the heightened risk. These include:
Radon Exposure, the leading cause
For people who never smoked, radon is the single largest known cause of lung cancer in the United States. It is a colourless, odourless radioactive gas that seeps up from soil and rock and collects inside homes. You cannot see it, smell it or taste it, and the only way to know whether your home has it is to test. The EPA estimates radon causes about 21,000 lung cancer deaths a year overall, and the CDC attributes roughly 2,900 of the annual never-smoker lung cancers to it. Unlike most risk factors on this page, this one is measurable and fixable.
Secondhand Smoke
Nonsmokers who live with or surround themselves regularly with smokers tend to inhale tobacco smoke. This can be just as damaging to the lungs as smoking oneself.
Asbestos Exposure
Similar to radon, asbestos is a natural mineral often found in insulation, automotive parts, and building materials. Prolonged asbestos exposure can result in trapped fibers in the body, resulting in severe health conditions, such as lung cancer and mesothelioma.
Family History and Genetics
A common question asked is, “Is lung cancer hereditary?” Possibly. Nonsmokers who have a close family member who developed the disease before the age of 50 have a greater risk of developing the disease than those without a genetic predisposition.
Air Pollution and Occupational Exposures
The CDC names air pollution among the established risk factors for lung cancer in people who never smoked. Workplace exposure to diesel exhaust, arsenic, chromium, nickel and silica also carries recognised risk. Chronic lung conditions such as COPD and pulmonary fibrosis have been associated with higher lung cancer risk in the research literature as well.
Not every nonsmoker is necessarily at risk of developing lung cancer. While some factors, such as those listed above, can increase one’s chances of developing the condition, there are individuals with no known risk factors who may still develop it.
Research is still ongoing as to the rise in lung cancer in nonsmokers and never-smokers, and indeterminate factors may be to blame.
Is Early Detection for Lung Cancer Possible?
Lung cancer, as with many cancers, is more likely to be treated successfully if found at an early stage – but how do you know when you may be at risk?
Stage 1 Lung Cancer Symptoms
The most common symptoms of lung cancer, in its early stages, may include:
- A worsening and/or consistent cough
- Coughing up blood
- Chest pain that gets worse with deep breathing, coughing, or laughing
- Hoarseness
- Loss of appetite
- Unexplained weight loss
- Shortness of breath
- Fatigue
- Infections (such as bronchitis or pneumonia)
If the lung cancer metastasizes, new symptoms may appear. This may include bone pain, jaundice, and swelling of the lymph nodes.
A Straight Answer About Screening
This is the part you came for, so we will not dress it up.
The only lung cancer screening test recommended in the United States is an annual low-dose CT scan, and it is recommended only for adults aged 50 to 80 with a 20 pack-year smoking history who currently smoke or quit within the last 15 years. If you never smoked, you do not meet those criteria, and no major medical body currently recommends routine lung cancer screening for you by any method.
That is a real gap and we are not going to pretend otherwise. We are also not going to tell you our scan closes it.
MRI is poor at looking at lungs. Lung tissue is mostly air, which returns very little MRI signal; the countless air-tissue boundaries inside the lung distort the magnetic field; and the lungs move constantly with breathing. In studies using dedicated chest MRI protocols, sensitivity for nodules 4 millimetres or smaller was about 57 percent, reaching 100 percent only above 8 millimetres. The authors of that work concluded MRI is not ready to replace CT for lung nodule detection. And a whole-body screening scan is not a dedicated chest exam, so there is no basis to expect it to do better.
Early lung cancer is precisely the small-nodule problem. That is exactly where MRI is weakest.
What a Nonsmoker Should Actually Do
There is no screening programme for you, but there are four things that genuinely reduce your risk or catch problems earlier, and three cost almost nothing.
1. Test your home for radon. This is the highest-value action on the list. A do-it-yourself kit costs a few dollars at any hardware or home improvement store, and some states and counties give them away free. Most return a result in about two weeks. If your home reads at or above 4 picocuries per litre, the EPA recommends fixing it, and a contractor can install a vent system that brings the level down. It is the rare health risk you can measure yourself, at home, this week.
2. Know the symptoms and do not sit on them. See a doctor promptly about a cough that will not go away or that changes, coughing up blood or rust-coloured phlegm, chest pain, shortness of breath, wheezing, hoarseness, unexplained weight loss, or repeated chest infections. Coughing up blood warrants a call the same week. Most of the time these turn out to be something else and treatable, which is a reason to get checked rather than a reason to wait.
3. Say the words I have never smoked out loud to your doctor. Lung cancer in never-smokers is often diagnosed later, partly because neither patient nor clinician has it near the top of the list. If you have persistent respiratory symptoms, ask directly whether lung disease has been ruled out. You are not being difficult; you are giving your doctor information that changes how the picture is read.
4. Cut your exposure where you can. Do not let people smoke inside your home or car. The CDC attributes about 7,300 never-smoker lung cancers a year to secondhand smoke, more than to radon. If your work involves asbestos, diesel exhaust or silica, use the protective equipment and follow the exposure controls.
And if you did smoke, even a little, check whether you qualify for low-dose CT. Pack-years add up faster than people expect: a pack a day for 20 years, or two packs a day for 10, both reach the threshold. If you are close to the line, ask. It is the one lung cancer test with strong evidence behind it and it is significantly underused.
Where Our Scan Fits
A whole-body MRI looks broadly across the body without ionizing radiation and is genuinely good at soft tissue and solid organs. The lungs are not one of its strengths, and we would rather say that plainly than let you book a scan expecting it to answer a question it cannot answer.
If your concern is specifically lung cancer, start with a radon test and a conversation with your doctor. If you want a broad structural look at everything else, that is what we do, and you can schedule a scan or talk to our team first.
This article is for general education and is not medical advice.
Frequently asked questions
How common is lung cancer in nonsmokers?
More common than most people realise. About 229,000 people in the United States are diagnosed with lung cancer each year, and roughly 20,000 to 40,000 of those, about 10 to 20 percent, occur in people who never smoked or smoked fewer than 100 cigarettes in their lifetime. Lung cancers in never-smokers are disproportionately adenocarcinomas, a subtype that tends to form in the outer parts of the lung.
What causes lung cancer in people who never smoked?
Radon is the leading cause in the United States, a colourless odourless gas that seeps up from soil into homes, responsible for about 21,000 lung cancer deaths a year overall. Secondhand smoke accounts for roughly 7,300 never-smoker cases annually. Other established factors are air pollution, asbestos and other workplace exposures such as diesel exhaust and silica, and inherited genetic changes.
Is there a lung cancer screening test for nonsmokers?
No. The only recommended test is annual low-dose CT, and eligibility requires being 50 to 80 with a 20 pack-year smoking history and either currently smoking or having quit within 15 years. Never-smokers cannot meet the pack-year threshold, and no major body recommends screening them by any method. That is a genuine gap in current guidance.
Can an MRI detect lung cancer?
Poorly, and it is not the right test. Lung tissue is mostly air, which returns very little MRI signal, the air-tissue boundaries distort the magnetic field, and the lungs move with every breath. In studies using dedicated chest MRI, sensitivity was about 57 percent for nodules 4 millimetres or smaller and reached 100 percent only above 8 millimetres. A whole-body screening scan is not a dedicated chest exam and should not be expected to do better. CT, not MRI, is the standard for lung nodules.
What should I do if I am worried about lung cancer and never smoked?
Test your home for radon, which is cheap and actionable. Learn the symptoms and see a doctor promptly about a persistent or changing cough, coughing up blood, chest pain, breathlessness, hoarseness or unexplained weight loss. Tell your doctor explicitly that you have never smoked, because never-smoker lung cancer is often diagnosed late partly because it is not near the top of the list. And reduce secondhand smoke and occupational exposure where you can.
