What Causes Lung Cancer in Nonsmokers?

Lung cancer is most often associated with smoking, but nonsmokers can also be at risk. Approximately 10–15 percent of lung cancer patients in North America are nonsmokers, according to the National Institutes of Health, with adenocarcinoma and squamous cell carcinoma being the most common types of lung cancer found in that population.

What causes lung cancer in nonsmokers? What should a nonsmoker do to prevent or detect lung cancer? We spoke with Michael A. Spallone, M.D., thoracic surgeon at Palisades Medical Center and Hackensack University Medical Center, for answers.

Lung Cancer Risk Factors for Nonsmokers

“Identifying different risk factors can help inform prevention and treatment strategies,” Dr. Spallone says. 

Lung cancer risk factors in nonsmokers can include exposure to:

• Secondhand cigarette smoke: Smoke breathed in from other people’s burning tobacco products leads to more than 7,300 lung cancer deaths a year in the U.S., according to the Centers for Disease Control and Prevention.
• Cooking oil fumes: Cooking fumes contain harmful gasses that include carcinogens. Sobreathing in cooking fumes in a non-ventilated kitchen may increase your risk of lung cancer.
• Asbestos: Asbestos, a group of minerals found in some soil and rocks, occurs naturally as tiny, strong fibers. Inhalation of these fibers has been linked to lung cancer. 
• Residential radon gas fumes: Radon is a gas that has no smell or color. It occurs naturally outdoors but can escape from the ground to the air and into buildings and homes. Radon is more likely to cause lung cancer in smokers, but nonsmokers are also at risk. 
• Particulate matter air pollution: Exposure to particle pollution may increase a person’s risk of lung cancer, but this is a more significant risk in countries without air-quality regulations.
• Diesel exhaust: Lung cancer has been linked to diesel exhaust. Those at greatest risk have high exposure, such as toll booth workers, miners, railroad workers and mechanics.

Additionally, obesity and chronic lung disease such as asthma, COPD and tuberculosis may increase your risk for lung cancer, Dr. Spallone says.

Multiple studies have pointed toward a relationship between non-smokers and a family history of lung cancer. This suggests a role for genetic predisposition based on family history. In fact, according to the National Institutes of Health, approximately 8 percent of lung cancers are inherited or occur as a result of genetic predisposition.

“A person’s risk of lung cancer may increase if their parent or sibling has or had the disease,” says Dr. Spallone. “Having a parent or sibling with lung cancer doesn’t mean you will get lung cancer, but talk with your doctor about your family history of lung cancer—or any health concerns.”

When to Get Screened for Lung Cancer

Lung cancer screening is recommended for people who meet all of the following criteria:

• Current or former smoker who has quit in the last 15 years
• Between the ages of 50 and 80 years old
• No symptoms of lung cancer 
• Have at least a 20-pack-year smoking history, such as two packs per day for 10 years, or one pack a day for 20 years

The U.S. Preventive Services Task Force does not recommend lung cancer screening for people who have never smoked. "We have yet to develop a system to identify those non-smokers who would benefit the most from a lung cancer screening program,” Dr. Spallone says. “With such scans for the general population as a whole, the current benefit may not outweigh potential risks, such as false positive results."

Instead, he recommends that nonsmokers discuss their personal risk factors with a primary care doctor while taking steps to reduce their risk by making healthy lifestyle choices and reducing exposure to cancer-causing agents, such as asbestos, secondhand smoke, diesel exhaust and air pollution.

Next Steps and Resources:

• Meet our source: Michael A. Spallone, M.D.
• Schedule a lung cancer screening in NJ.