Lung Cancer in Nonsmokers

This information is useful for adults
woman coughing, possibly because of lung cancer even though she is a non- or never-smoker

If you have never puffed on a cigarette in your life, you may think you won’t get lung cancer. And it’s true that the odds of avoiding lung cancer are in your favor—but some nonsmokers get it anyway. According to the American Cancer Society, as many as 20 percent of people in the United States who died from lung cancer in 2018—a total of roughly 30,000 people—never smoked.

A nonsmoker is a person who doesn’t currently smoke, but may have smoked 100 or so cigarettes at some point in their life. There are also people who are considered never-smokers, who have never smoked or who have smoked fewer than 100 cigarettes in their lifetimes. Smokers and non/never-smokers tend to develop different types of lung cancer; the latter group is more likely to develop lung cancer as a result of a genetic mutation or abnormality.

In the past five to 10 years, new knowledge about lung cancer has changed the way it is treated in both smokers and nonsmokers. “We used to think all lung cancers were the same, but now we understand that there are different kinds,” says Anne Chiang, MD, PhD, a Yale Medicine thoracic medical oncologist, and chief network officer and deputy chief medical officer for the Smilow Cancer Hospital and its Care Centers. “The good news is that the types of lung cancer that nonsmokers tend to get are usually driven by a molecular change or mutation that can be detected in the tumor, and there are drugs and therapeutics available for them. At Yale, we have a very active research program aimed at targeting those cancer cells that contain the mutation.” 

Lung cancer, one of the most common cancers in the world, is a leading cause of cancer-related death in men and women in the United States. While smoking cigarettes is by far the most common cause of lung cancer, risk factors also include a family history of lung cancer and certain environmental contributors.  

Like all cancers, lung cancer begins at the cellular level and is the result of abnormal cells that reproduce rapidly and out of control. It can start in one area of the body (in this case, the lungs) and spread (or metastasize) to other organs or the bones.

Primary lung cancer refers to cancer that starts in the lungs, of which there are two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Named initially for how the cancer cells look under the microscope, these two types account for most of the 230,000 newly diagnosed cases of lung cancer in the U.S. each year.

The vast majority of lung cancers (80 percent) are non-small cell cancer. Smokers tend to get a type of NSCLC called squamous cell (which accounts for more than half of lung cancers diagnosed in smokers). Most nonsmokers, on the other hand, are diagnosed with a different non-small cell type known as adenocarcinoma.