Lung cancer is one of the most common cancers in the world and is a leading cause of cancer-related death in men and women in the United States according to the American Cancer Society. Although cigarette smoking is the main cause of lung cancer and quitting would prevent a large number of lung cancer cases, it wouldn’t prevent all of them.

recent study led by researchers at the National Cancer Institute suggests that about 10% of men and 20% of women who develop lung cancer have never smoked and that there are three molecular subtypes of lung cancer in people who have never smoked.

Scientists are still unlocking the mystery of how lung cancer arises in people who have no history of smoking, but here’s what we do know. Missak Haigentz, Jr., MD, chief of thoracic and head and neck medical oncology at Rutgers Cancer Institute of New Jersey, clinical director of Oncology Integration at RWJBarnabas Health, professor of medicine at Rutgers Robert Wood Johnson Medical School, and attending physician at Robert Wood Johnson University Hospital New Brunswick, shares some insight.

Q: How is cancer in nonsmokers different than that of a smoker?

Missak Haigentz: Lung cancer in smokers is often caused by exposure of carcinogens in tobacco smoke across years, if not decades of tobacco use. As a result, there are multiple genetic changes that arise in the cells that line the lungs that give rise to lung cancer. Lung cancer does, however, happen from other known exposures, for example, radon gas or secondhand smoke, as well as from others. 

What we know already is that lung cancers, despite appearing similar under the microscope, may develop differently in never smokers, and this information on molecular differences has already had a tremendous impact in the way we treat the disease with targeted cancer therapies.

Q: What do we think may cause lung cancers in nonsmokers?

Haigentz: Anything that we inhale can potentially expose our airways and our lungs to damaging agents that may give rise to cancer—we have not yet identified all of these. While there is still information on this topic being explored, we know that exposure to radon gas is a known risk factor for the development of lung cancer.

Some other causes may include asbestos exposure, which portends a risk for a certain kind of cancer called mesothelioma, which is a very rare type of cancer that occurs in the thin layer of tissue that covers the majority of your internal organs. Heavy secondhand smoke is also a risk for lung cancer development.

Q: What is the advantage to identifying distinct molecular subtypes of lung cancer and why is this topic important for researchers to explore? 

Haigentz: Supporting science and identifying molecular subtypes give us great insight into how these cancers are formed in the first place. What we really want is to prevent this type of cancer before it starts. This research also helps us understand how smokers and never smokers can benefit from treatments such as targeted cancer therapeutics that have been identified to target specific tumor molecular abnormalities. 

Based on the molecular features of lung cancers, we have recently developed several effective treatment options targeting its biology, and as a result of ongoing scientific investigations even more exciting treatment advances are anticipated.

Q: What can nonsmokers do if they are worried about lung cancer?

Haigentz: If you’ve never smoked, first don’t ever start! We can also test our homes for radon gas and be mindful of the air we expose ourselves to. We now recommend lung cancer screening with yearly low dose CT scans for those who have had significant exposure to smoking, and there are a growing number of former smokers who can benefit from this potentially life-saving technology. 

Most importantly, we need to remove the stigma of lung cancer; understand that there are people who have smoked their whole life and never develop cancer, and there are people who have never smoked at all who develop lung cancer. Anyone with lungs can get lung cancer. I tell my patients that regardless of whether they have smoked, nobody deserves cancer, and everyone deserves the best care possible.