Authored by JoannaRasmuson

Common Causes and Risk Factors for Lung Cancer in Smokers and Nonsmokers

November 29, 2021 | Cancer CenterPulmonology

Lung cancer is the leading cause of cancer deaths around the world. While 80% of lung cancer deaths are caused by smoking, lung cancer can occur in people who have never smoked or had exposure to secondhand smoke. About 20,000 to 40,000 people who have never smoked or smoked fewer than 100 cigarettes in their lifetime contract varying types of lung cancers.

Common symptoms of lung cancer

Lung Cancer symptoms are generally the same for every patient, whether you have smoked or not. Some common symptoms include:

  • Feeling unwell or feeling tired all the time
  • Frequent coughing
  • Coughing up blood or rust-colored sputum (spit or phlegm)
  • Chest pain
  • Wheezing
  • Shortness of breath
  • Unexplained or dramatic weight loss
  • Loss of appetite
  • Respiratory infections, like bronchitis or pneumonia, that don’t go away

Factors that increase your risk of lung cancer

Most people with lung cancer either formerly smoked or were exposed to secondhand smoke over a long time. While it is rare for someone who has never smoked to contract the disease, it can still happen. Several factors can increase the risk of lung cancer. Some of these factors can be controlled, such as quitting smoking. However, other factors cannot be controlled like your family history and air pollution. Some of the most common risk factors for lung cancer include:

  • Smoking: Your risk for lung cancer increases with every cigarette you smoke each day. Quitting can significantly lower your risk of lung cancer, regardless of the age you decide to quit.
  • Secondhand smoke exposure: Even if you don’t smoke, your risk for lung cancer increases if you are exposed to secondhand smoke over a long period.
  • Previous radiation therapy: If you have had radiation therapy to the chest for another type of cancer, you may be at risk of developing lung cancer. If you are worried about the adverse effects of your radiation therapy, consult with your doctor.
  • Radon gas exposure: Radon is the #1 cause of cancer in non-smokers. Radon is formed by the natural breakdown of soil, rock, and water. Eventually, radon becomes part of the air we breathe. Small levels of radon will not cause damage to your respiratory system, but unhealthy levels can cause lung cancer in some people. If you are interested in learning more about the effects of radon on your lung health, visit the American Lung Association.
  • Unhealthy exposure to asbestos and other carcinogens: You may have an increased risk of lung cancer if you work in an environment where you are often exposed to arsenic, chromium, and nickel.
  • Family history of lung cancer: Those who have a parent, sibling, or child who has had lung cancer have an increased risk of contracting the disease.

Daniel Boffa, MD, a Yale Medicine thoracic surgeon, offers a helpful way to visualize the difference between cancers that affect smokers and cancers that affect nonsmokers. He says,

If you are a smoker, you can think of your lung as a bag of white marbles, and cancer is like putting a black marble in there. The type of cancer a nonsmoker gets is more like putting in black sand. Instead of a spot or a lump, it’s more like a hazy area. It’s more diffuse.

If you are experiencing any of the symptoms listed above or have been introduced to high levels of radon or asbestos, contact your primary care physician. If you have already faced cancer but are still experiencing symptoms, your oncologist can work with you to develop a healthcare plan. Part of that plan may include PET-CT scans that can check for signs of cancer recurrence. For more information regarding the benefits and risks of PET-CT scans, visit the Revere Health blog.

If you are in need of any care related to your respiratory system, the Revere Health Pulmonology team will be happy to assist you.

Lindsey LeBaron


Lindsey LeBaron

Lindsey LeBaron has been working as the Marketing Assistant for Revere Health for the past three years. Lindsey has a bachelor’s degree in social sciences at Brigham Young University and will graduate with her master’s degree in global strategic communications at Florida International University in December 2021. Coupled with her master’s degree, Lindsey is also working on a certification in crisis management and consensus-building. Recently, she was awarded the honor of joining the National Communications Association as a member of the Lambda Pi Eta honor society. Lindsey is passionate about building lasting connections between communities to create lasting change and believes that communication is a vital element to building long-lasting relationships. When she is out of the office, Lindsey enjoys singing and playing the piano, going on adventures, traveling to new locations, and reading books about world affairs.

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This information is not intended to replace the advice of a medical professional. You should always consult your doctor before making decisions about your health.