Not smoking is still the best way to lower your risk of lung cancer. But doctors are seeing something unexpected: more people who have never smoked are being diagnosed with the disease.
“It’s estimated now that close to a third of all lung cancer cases worldwide are attributable to risk factors that are not at all related with cigarette smoking or tobacco use,” said Dr. J. Nicholas Bodor, assistant professor in the Department of Hematology/Oncology and co-founder of the Never Smokers Lung Cancer Clinic at Fox Chase Cancer Center.
A growing trend among never-smokers
It’s not yet clear whether more never-smokers are actually developing lung cancer, or if they simply make up a larger share of cases because fewer people smoke overall. In 2000, about one third of adults worldwide smoked. By 2022, that had dropped to one fifth, according to the World Health Organization.
“We don’t exactly know,” Bodor said. “But what is without question is that, from a clinician standpoint, we are seeing more individuals with little to no smoking history who are developing lung cancer.”
The exact reasons are not clear, but researchers have identified several possible contributors.
Possible reasons behind the rise
Some likely factors include:
• Radon: An invisible, odorless gas common in Pennsylvania that seeps into homes from the ground. The only way to know if levels are high is to test.
•Air pollution and secondhand smoke: Both can increase lung cancer risk.
•Biology and genetics: Women are more than twice as likely as men to develop lung cancer without smoking. Rates are also climbing among nonsmoking Asian American women.
Bodor and his colleagues at Fox Chase have done preliminary research that suggests that some people metabolize the hormone estrogen in a way that may produce cancer-causing byproducts.
Limited - Temple Health Lung Cancer Infographic
“There's one in particular called 4-OHE, or 4-hydroxy estrogen metabolite, that we've actually been finding at higher levels in individuals with lung cancer with no smoking history as compared to cancer-free, healthy, control individuals,” he said.
“There's a lot of research looking into potential risk factors that might be causing lung cancer among never-smokers but there's still a lot that we need to learn,” he added.
Why diagnosis is harder for nonsmokers
Lung cancer in nonsmokers is often caught late, when it is harder to treat. Screenings usually are not covered for people under 50 who do not smoke, since their risk is considered low. On top of that, many never-smokers do not believe they could be at risk. Because they are otherwise healthy, they may brush off early warning signs or delay seeing a doctor.
Some symptoms, such as coughing up blood, are difficult to ignore. But others, including a lingering cough, chest pain that does not go away, or unexplained weight loss, are easy to dismiss. Even recurrent infections can sometimes be a clue. In fact, a lung infection may be a blessing in disguise if it leads to an imaging test that spots cancer early.
“The key is really just any symptom that seems odd, something that’s bothersome,” Bodor said. “Don't brush it off, talk to your doctor about it.”
Hope in treatment options
A lung cancer diagnosis can be shocking, especially for someone who never smoked. But Bodor stresses that there are reasons to stay hopeful.
“Maintain hope and optimism,” he said. “We do have potentially really good treatments for lung cancer that occurs among individuals with little to no smoking history.”
For nonsmokers, targeted therapies, medications designed to attack cancer cells based on their genetic makeup, are often the best option. These treatments are chosen after doctors run molecular tests on the tumor.
“It’s absolutely critical that testing is done up front in order to choose the best treatment for an individual,” Bodor said.
The message for smokers: it is never too late to quit
While the trend among nonsmokers is concerning, smoking is still the leading cause of lung cancer. For smokers, Bodor’s advice is clear: quit, no matter your age or diagnosis.
“At Fox Chase, we have a tobacco cessation program that I'm a strong supporter of and very proud of,” he said. “It's been open to individuals with really no cancer history who are looking to quit, but it's also open to individuals with underlying cancer who are looking to quit, because the benefits of quitting smoking are huge and really, there's no bad time to quit.”
Specialized care at Fox Chase
If you notice unusual or persistent symptoms, talk with your primary care doctor first. If lung cancer is suspected or diagnosed, Fox Chase Cancer Center offers expert evaluation, advanced treatment options, and access to clinical trials. Learn more or request an appointment at Fox Chase Cancer Center.