Why Are More Non-Smokers Getting Lung Cancer?

What’s causing lung cancer in non-smokers?

While smoking remains the leading risk factor for lung cancer, diagnoses like Murrell’s are becoming more common in non-smokers. Up to 2 out of 10 lung cancers (20,000-40,000 per year) are being diagnosed in people who never smoked or smoked fewer than 100 cigarettes in their lives. Lung cancer is also more likely to occur in people over 65, with 70 being the average age of diagnosis, but younger women are now being diagnosed with lung cancer at higher rates than their male counterparts — especially among non-smokers.

Norman Edelman, M.D., a professor of medicine at Stony Brook University who studies pulmonary diseases, said the answers aren’t clear on why lung cancer rates are increasing among non-smokers, but those exposed to particle pollution face the highest risk.

“Environmental pollutants increase the risk of lung cancer likely the same way as cigarettes, as oxidant chemicals disrupt the cells’ DNA,” Edelman said. “Although research is limited to pollutants which are monitored, fine particles are the most studied and the most implicated.”

While secondhand smoke — exposure to other people’s smoking — can be a factor in lung cancer development, environmental factors such as radon, air pollution, smoke from wildfires and fine particulate matter are increasingly being connected to cases in non-smokers. The Environmental Protection Agency says radon — radioactive gas that seeps into homes — is the top cause of lung cancer in non-smokers, contributing to about 2,900 lung cancer deaths in non-smokers each year.

More research is also connecting genetic factors to lung cancer development, with studies showing how air pollution triggers lung cancer development in cells with certain genetic mutations. While Murrell’s short trip to India likely didn’t cause her lung cancer, she believes the change in air quality and a weakened immune system from the trip triggered the symptoms that led to her diagnosis.

Continuing research into genetic mutations could provide more insight on links between pollution and lung cancer in non-smokers. Murrell said she has the HER2 mutation, which is most common in people with breast cancer, although up to 2% of lung cancer patients have the HER2 mutation. More common cell mutations in lung cancer patients are ALK or EGFR.

Read: Understanding the Different Types of Lung Cancer >>

When Murrell was in the hospital for her initial treatment, she tried to figure out the cause of her cancer. She remembers filling out a questionnaire asking if she’d worked in a factory or lived in an area with high pollution or coal mining — none of which applied. She lived in Iowa for seven years, and read that Iowa had the fastest growing rate of new cancers in the U.S. Could she have been exposed to agricultural-related pollutants years ago?

“I don’t have an answer for my case particularly,” Murrell said. “I was never around secondhand smoke. I was not in a hazardous job. I don’t think I was exposed to radon since I moved a lot and only lived in the same house for about two years my entire life. I just don’t know.”

Reducing your risk of lung cancer

While anyone can develop lung cancer, people of color — especially women — have worse outcomes from the disease, often because they’re less likely to get an early diagnosis or receive treatment, according to the American Lung Association. This is the case even when they’re experiencing common lung cancer symptoms like a worsening cough, chest pain, shortness of breath, wheezing, coughing up blood and fatigue.

Murrell encourages anyone experiencing those symptoms to see a healthcare provider immediately, although she’s aware of multiple survivors who went years being misdiagnosed. By the time they received a diagnosis, they were at stage 4.

“If you have those symptoms and they’re not going away with just normal treatments, be really persistent and push for more investigation,” she said.

Read: Doctors Shrugged Off My Cough Because I Wasn’t a Smoker — but I Had Stage 4 Lung Cancer >>

Edelman also encourages those eligible to be screened for lung cancer. “CAT scan screening has been successful. Over the past decades, the five-year survival rate from lung cancer has increased,” he said.

To be eligible for annual screening under current U.S. Preventive Services Task Force guidelines, you must be between the ages of 50 and 80, currently smoke or have quit within the past 15 years, and must have a 20 pack-year smoking history. (A pack year is the equivalent of smoking a pack [20 cigarettes] a day, every day for a year. A person could have a 20-pack year history by smoking a pack a day for 20 years or smoking two packs a day for 10 years ). These criteria, however, can leave out a large number of people without risk factors.

Murrell knows of younger women with a family history who were turned down for screening, and she notes how she didn’t have any of the typical lung cancer symptoms that would have led to a provider suggesting a screening. The only early sign she recognizes now was a blood clot in 2023 that HCPs said could be related to birth control use or sitting for long periods of time on another airplane trip. She believes now the clot was likely an early sign of lung cancer.

Today, Murrell and her husband are living in Park City, Utah, where she can be closer to an NCI-Designated Cancer Center for treatment. She calls her life “pretty normal” despite her diagnosis, and she still hikes four miles a day, lifts weights and works full time. She attributes her good health to her lifestyle before her cancer treatment and is thankful she’s able to continue doing the things she enjoys.

She’s also become an advocate with the Young Lung Cancer Initiative, which she found as a source of support while undergoing treatment. On their website and social media, she read multiple stories of people doing well years after a stage 4 diagnosis.

“The Young Lung Cancer Initiative really stood out to me,” she said. “Initially upon my diagnosis at my local hospital, I was given nine months to live, but seeing people’s messages gave me a lot of hope for this journey. I’m so fortunate I found the group so early on.”