While smoking is the number one risk factor for lung cancer, recent research shows the rates of lung cancer in people who have never smoked (aka never-smokers) are steadily climbing. A study published in January 2017 in the Journal of the National Cancer Institute found an estimated 10 to 15 percent of lung cancer occurs in never-smokers, and that the incidence of non-small-cell lung cancer (NSCLC; the most common type) in never-smokers is on the rise, increasing by 8 percent between 1990 and 1995 and by 14 percent between 2011 and 2013. In fact, as many as 20 percent of people who die from lung cancer each year have never smoked or used any form of tobacco, according to the American Cancer Society. Women never-smokers are more susceptible than men, according to the statistics: Women who have never smoked have twice the risk of developing lung cancer as men. In fact, a study published in September 2020 in Lung Cancer Management showed that nearly half of women diagnosed with lung cancer worldwide are never-smokers, compared with only about 15 to 20 percent of men. What’s behind the surge in cases among never-smokers? The explanation is complex, likely due to many factors, and not fully understood, says Andrew Kaufman, MD, a thoracic surgeon at Mount Sinai Hospital in New York City. “We know very little about why this is occurring, and why it seems to be occurring at higher rates now compared with historical time points,” he says.
Top Reasons Why More Never-Smokers Are Getting Lung Cancer
There are most likely many causes that contribute to the increase in lung cancer cases among never-smokers. Here are some possible reasons:
Simple Math “The number of people who never smoked as a proportion of the general population is higher now than ever in the last 100 years because the rates of smoking have declined to about 20 percent of the adult population,” says Dr. Kaufman. “So, with less people having a history of smoking, there is a higher chance for diagnosing lung cancer that is not attributable to smoking.”Genetic Mutations People who have never smoked are more likely to have genetic mutations — changes in the DNA that makes up a gene — that contribute to cancer development. “Many never-smoking lung cancers harbor genetic mutations known as ‘driver mutations’ that cause otherwise healthy lung cells to become cancerous,” says Kaufman. “But we don’t know what causes these mutations to occur.” Common mutations in never-smokers who develop lung cancer include glitches in EGFR, ALK, ROS1, and more. The good news is there are drugs and therapies available to target a lot of these mutations.Family History People with a family history of lung cancer have a greater risk of developing the cancer themselves. This is especially true if you have a first-degree relative (a parent, sibling, or child) who developed lung cancer before age 50.Radon Exposure Radon is a naturally occurring radioactive gas that trickles into homes from the ground. Researchers at Yale Medicine estimated radon gas exposure accounts for about 21,000 lung cancer deaths each year. Exposure to radon is the second leading cause of lung cancer but the most common cause of lung cancer in nonsmokers, according to Providence Health. Some recent studies, such as one published September 2019 in Scientific Reports, have suggested that modern building construction practices have led to an increase in the amount of radon concentration in homes. The Environmental Protection Agency (EPA) estimates that 1 out of every 15 homes in the United States has unsafe levels of radon.More Screening Doctors may be detecting more lung cancers in people who have never smoked because of the increased use of screening technologies. “We image people for so many things unrelated to lung cancer that we end up finding things incidentally,” says Kaufman. “Someone’s kidney stones may save their life if a spot on the lung is noticed and the appropriate diagnosis and care is followed through.”Secondhand Smoke Secondhand smoke, smoke breathed in from another person’s cigarette or tobacco product, accounts for about 7,000 lung cancer deaths each year in the United States, per Yale Medicine. Researchers are also looking at the impact of “thirdhand smoke.” This is the film of nicotine and chemicals that may be left on walls, furniture, clothing, and other surfaces.Other Environmental Pollutants Other environmental factors, such exposure to air pollution, diesel exhaust, asbestos, and arsenic may lead to lung cancer in people who don’t smoke.
How Can You Lower Your Chances of Developing Lung Cancer?
Never-smokers can help lower their risk of lung cancer by avoiding secondhand smoke and exposure to radon or other harmful pollutants. It’s also important to seek medical care if you develop any early symptoms, because lung cancer, especially, is a disease that is most easily treated when caught early. Symptoms to look out for include:
A nagging, persistent coughCoughing up bloodLoss of energyUnexplained weight lossShortness of breathChest pain
“Awareness is everything. Diagnosis at any early, curable stage is critical,” says Kaufman. “Don’t hesitate to see your doctor if you develop symptoms.”
