Now, emerging research continues to point to multiple factors of why hundreds of thousands of people worldwide are dying from the disease each year. The World Cancer Research Fund (WCRF) reports lung cancer as the most common cancer across the globe, attributing most of the cases to people in China, the United States and Japan from data released in 2022. The Journal of Thoracic Oncology says 1.8 million people die each year from lung cancer.

Between 10-20% of patients diagnosed with lung cancer are non-smokers.

In part one of this two-part series, Jun Zhang, MD, PhD, a thoracic oncologist and the vice president of oncology research with OSF HealthCare Cancer Institute, discusses five main reasons that patients who do not smoke are being diagnosed with lung cancer. Part one discussed both PM2.5 (Particulate matter) and radon levels being major causes of lung cancer among nonsmokers, while this article will dive into the next three categories.

#3: Cooking fumes leading to lung cancer

The World Health Organization (WHO) reports that each year, 2.9 million people die prematurely from illnesses caused by household air pollution, specifically by the “incomplete combustion of solid fuels and kerosene used for cooking.”

Of those deaths, 6% are from lung cancer, the WHO says, adding that roughly 11% of lung cancer deaths in adults are attributed to “carcinogens from household air pollution caused by using kerosene or solid fuels like wood, charcoal or coal for household energy needs.”

"This is one of the reasons there's a higher incidence among Asian people, because of cooking style and the importance of food," Dr. Zhang says. "Over there, the way we cook delicious food is using the really hot wok (large bowl-shaped pan used for high-heat cooking) as the way to cook. Especially if the cooking involves using animal fat, it can create droplets (fumes), that can be inhaled and cause problems." 

#4: Secondhand smoking

Just as there is no safe level of smoking, the same can be said for secondhand smoke (SHS). The U.S. Centers for Disease Control & Prevention (CDC) says even brief exposure to SHS can be harmful. This should be a wakeup call to both smokers and those who are around smokers, and lung cancer isn’t the only health concern.

The CDC reports other health problems that can be caused by secondhand smoke (in adults who don’t smoke) are coronary heart disease, stroke, as well as reproductive health effects in women. For infants and kids, SHS can cause sudden infant death syndrome (SIDS), respiratory infections, ear infections and asthma attacks.

Especially in the 1940s through 60s, smoking was seen more broadly as "cool" and was a norm in many American households. So, secondhand smoking, Dr. Zhang says, is another major contributor to non-smoking lung cancer diagnoses. 

"Whether it's a parent smoking or a coworker smoking, this leads to indoor air pollution," Dr. Zhang points out. 

SHS causes more than 7,300 lung cancer deaths each year in American adults who don’t smoke and increases the risk of lung cancer in adult non-smokers by 20-30%.

#5: Genetic predispositions

Your genes can play a role in your cancer risk as well, Dr. Zhang says. A family history of lung cancer in a first-degree relative account for approximately 25% of attributable risk in never-smokers – the largest single risk factor. The germline variants in certain genes like EGFR and STK11 can increase lung cancer susceptibility among never-smokers.

Dr. Zhang says with genetic testing, these variants can be found.

"It turns out that if you have germline variants in the EGFR gene, people have a higher susceptibility to have lung cancer," Dr. Zhang says. "With AI (artificial intelligence) and more in-depth sequencing, we'll be able to find more genetic predispositions."

STK11 (also known as LKB1) is another prominent gene that its germline variants my result in increased susceptibility in many non-smoking lung cancer patients. Germline mutation of this gene can lead to Peutz-Jeghers Syndrome, which leads to the growth of polyps in the gastrointestinal (GI) tract or other parts of the body. It also increases lung cancer susceptibility regardless of environmental exposures.

Current screening guidelines

Low-dose CT scans are available for certain patients, but the current guidelines require you to be at least 50 years of age and have a 20-year smoking history (one pack of cigarettes a day for 20 years, of ½ pack of cigarettes for 40 years). You also need to either be a current smoker or have quit in the last 15 years. 

Dr. Zhang says findings like this argue for expansion of lung cancer screening criteria, especially among Asian females, which is aligned with the findings from FANSS (Female Asian Nonsmoker Screening Study), which screened 1,000 eligible Asian women, ages 40-74. Using low-dose CT (LDCT), the findings showed a lung cancer detection rate of 1.3%. This was higher than a separate study called the National Lung Screening Trial (NLST) which studied high-risk smokers.

Dr. Zhang says that if you have any concerns like lingering cough that lasts for multiple weeks, talk to your primary care provider (PCP). You can get a chest X-Ray to make sure you don't have pneumonia.

You could also have GERD (acid reflux), and these are important to be seen for. If none of the common benign cases are identified, this is where patients should advocate for themselves and ask for a CT scan to check for lung cancer.

Video Interview Clips

"Anyone that has lungs has a chance of lung cancer,” says Jun Zhang, MD, PhD, vice president of oncology research with OSF HealthCare Cancer Institute.

In fact, 10-20% of lung cancer patients are people who have never even smoked, Dr. Zhang adds. 

"Lung cancer is generally referred to as a 'smoker's disease.' But it turns out now that we're seeing more lung cancer patients without a history of smoking," Dr. Zhang observes. "If we put lung cancer in patients who have never smoked in a separate category, this can be listed as the number five cancer killer in the world." 

This translates to roughly 40,000 Americans every year being diagnosed with lung cancer, despite never smoking cigarettes. 

Women of Asian descent who don't smoke tend to be impacted more by this, Dr. Zhang says, compared to the rest of the population. Research shows that 57% of Asian American women diagnosed with lung cancer have never smoked. Based on this, in a recent study called FANS (Female Asian Never Smoker), researchers at the University of California San Francisco (UCSF), UC Davis and Stanford University are investigating why Asian American women who have never smoked develop lung cancer at unusually high rates compared with other populations.

Sadly, Dr. Zhang says, people who present with lung cancer but have never smoked, are presenting at a later stage. 

"Those patients present to us, at least at my clinic, and they already missed the chance of an early diagnosis. Early symptoms can be cough and shortness of breath, but quite often people are not paying attention to this because they don't smoke and they don't have a chance to get screened," Dr. Zhang says. "That's the sad story, that even though they've never smoked, at the time when they're diagnosed with lung cancer, it's almost always at late stage." 

So, why is this happening? Dr. Zhang discusses five main reasons that non-smokers are getting diagnosed with late-stage lung cancer. The top two culprits will be laid out in this article, with three more to come in part two.

#1: PM2.5 (Particulate Matter)

PM2.5 is the top contributor to non-smokers diagnosed with lung cancer worldwide. The U.S. Environmental Protection Agency (EPA) describes PM2.5 as fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller.

"If you inhale the particles, you cannot get them out of your body. It can get into your lungs, be trapped there, and even get into your circulation and cause problems," Dr. Zhang says. "If we're thinking about cigarette smoking as the number one reason for lung cancer, globally PM2.5 is the second most common reason for lung cancer." 

In the United States, the EPA sets and reviews national air quality standards for PM2.5.

The Upper Midwest region has been below the national average for many years, and according to the EPA, has seen an improvement in air quality since at least 2000. The EPA's national standard is set at 9.0 micrograms per cubic meter. Dr. Zhang says for every 10 microgram per cubic meter increase, it increases lung cancer mortality by 20%.

Some areas in the world can be up to 100 micrograms per cubic meter; Dr. Zhang points out. Vehicle exhaust and industrial emissions along with outdoor fires contribute to these levels. 

The American Cancer Society (ACS) reports lifetime exposure to PM2.5 might increase the risk, and even speed up the onset of various cancers, including lung cancer.

#2: Radon levels in the home

While high PM2.5 levels are the #2 cause of lung cancer worldwide, here in the United States, the second-leading cause of lung cancer (next to smoking) is due to high radon levels. 

According to the ACS, radon is a colorless and odorless radioactive gas. Radioactive elements such as uranium found in soil and rock break down, then move the radon gas from the soil and rock into the air, ground water and surface water.

When radon breaks down in the air, it gives off radiation that can damage DNA in our cells.

“Radon is released by radioactive materials underground, but then they accumulate in the house, especially if it doesn't have good ventilation," Dr. Zhang says. 

The U.S. Centers for Disease Control & Prevention (CDC) says testing for radon in your home is the only way to know if levels are high. It’s recommended to get this testing done before or as soon as you move into the home.

Dr. Zhang says findings like this argue for expansion of lung cancer screening criteria. 

He adds that if you have any concerns like lingering cough that lasts for multiple weeks, especially with shortness of breath, talk to your primary care provider (PCP). You can get a chest X-Ray to make sure you don't have pneumonia.

GERD (acid reflux) and some heart issues could also be a possibility, and these are important to check out. If none of these things exist, this is where patients should advocate for themselves and ask for a CT scan to check for lung cancer that can show if a nodule or mass is present.

To learn more about the Lung Cancer Program at OSF Cancer Institute, or to schedule an appointment, visit the OSF HealthCare website.

Video Interview Clips

A new generation of 3D Virtual Reality (VR) imaging technology at OSF HealthCare is giving surgeons a clearer view of cancer than ever before – and in some cases, completely changing surgical plans. For OSF HealthCare thoracic surgeon Richard Anderson, MD, that level of insight recently made the difference between removing part of a patient’s chest wall and preserving it entirely.

Dr. Anderson, chair and Norman Estes Professor of Surgery at University of Illinois College of Medicine Peoria, says the leap from standard imaging to 3D modeling is transformative for surgeons.

A better view

“So the real difference between a 2D and 3D is, just imagine looking at something on a piece of paper with two different pictures, looking at it from side to side, as opposed to having a model in your hand and being able to take that model and move it all around in all different directions, upside down, inside out, even open up things within the model and look at it. It’s really the difference between 2D and 3D.” Dr. Anderson adds, “It’s really quite impressive.”

The technology allows his team to isolate tumors, peel away layers of anatomy, and examine the intricate relationships among bones, vessels, and muscle before they ever enter the operating room. That clarity is especially crucial in complex thoracic oncology, where anatomy is delicate, variable and easily injured.

For Dr. Anderson and others who use 3D imaging, it increases the surgeon’s confidence.

“In the more complex oncology cases, it can make a big difference. It can help the surgeon really identify what structures they have to worry about during the operation, what structures they might have to sacrifice, before they actually do the operation and gives them a little bit more level of confidence going into the operation than probably they would have before.”

A tumor in a rare location

That level of detail proved critical in a recent complex thoracic oncology case. Thoracic surgery presents unique challenges because of the delicate and complex anatomy of the chest.

“The arteries aren't made the same, and so they're easier to tear. They're much more delicate. Lung tissue is sometimes like tissue paper, too. It’s easy to injure and tear. You have got to be very careful when you do the dissections in thoracic surgery. That's what makes it so challenging.”

Dr. Anderson treated Jake Wilson, a 69-year-old retired farmer and former prison guard from Central Illinois. Wilson’s case was challenging. He was diagnosed with a rare form of lung cancer and in August of 2025 began a series of chemotherapy and radiation to shrink the aggressively growing tumor.

Still, as surgery approached, Dr. Anderson was challenged with removing a nearly six‑centimeter tumor (about the size of a small egg) situated high in the chest, closely hugging the first three ribs. Standard 2D scans suggested the cancer had invaded the bone – a scenario that would typically require removing three ribs to ensure the cancerous tumor was completely removed.

Seeing is believing

But when Wilson became the first adult patient with lung cancer to have his case analyzed using advanced 3D modeling and virtual reality, the picture changed dramatically. The technology revealed that his ribs were not invaded at all. The tumor, though large and aggressive, was confined to muscle.

Sister M. Pieta Keller, Connor Davey, and Reid Jockisch, innovation engineers at Jump Simulation worked to segment the tumor for 3D viewing in virtual reality. Sister M. Pieta recently showed Wilson the 3D rendering. It was something he’ll never forget as she displayed his chest wall anatomy in vivid color and manipulated the images to reveal why Dr. Anderson could spare all three ribs.

“That was one of my biggest fears was losing my ribs,” Wilson explained. “Just the concept of that,” he said as his voice trailed off. Sister M. Pieta explained, “And your recovery and your pain would have been a lot higher,” to which Wilson responded, “I’m sure.” Sister M. Pieta added, “So this was quite the gift.”

After years of lung scans due to his history of smoking, seeing the vivid digital model after his successful surgery made the size and seriousness of the tumor undeniably real. Having only retired from farming six months earlier, Wilson admitted that going into the surgery, he was really scared.

“That put the fear of God into me, needless to say, because I’m an active person. I’m a farmer. I thought, ‘I could see being debilitated for the rest of my life.’”

A recovery that surprised everyone

The new imaging technology altered not only the surgical approach, but Wilson’s experience afterward. Instead of the severe pain typically expected after chest wall removal, his discomfort was minimal; it was largely limited to the area where an intercostal muscle was removed.

Wilson required only mild pain medication and never needed supplemental oxygen after losing half of his lung, something his care team described as highly unusual.

Even more astonishing, follow‑up imaging showed his remaining lung tissue had expanded far faster than expected. His post‑surgical biopsies revealed a remarkable result: the tumor was completely non‑viable (dead) at the time of removal.

A message about screening

Today, Wilson is cancer‑free and sharing his story. He credits many people along the way, including his primary care doctor, who five years ago, when Wilson was still smoking, encouraged him to get an annual CT screening to detect lung cancer.

“I thought, ‘I’m the one that’s stupid enough to do this to myself I ought to at least be smart enough to use a little preventive maintenance.’” He added, “And thank God I did because I might already be gone.”

But above all, Wilson returns to the strength of his faith which he credits with leading him to Dr. Anderson and his care team at OSF HealthCare Cancer Institute in Peoria and OSF Cancer Center in Bloomington. He is sharing his story to show the power of prayer and faith, and to instill hope.

“I know for a fact that the most important thing a person can have in these ordeals is hope because without hope you give up. And this is one time you can’t afford to give up because if you give up, you’re done,” Wilson declared.

For Dr. Anderson, the case represents the promise of 3D technology not just to guide surgeons, but to change outcomes. He calls that, “A good day at work.” And for Wilson, it represents something even bigger: a second chance he intends to use to encourage others to seek preventive screenings, face fear with hope and share gratitude for every day.

Video clips with Dr. Richard Anderson

Video clips with oncology patient Jake Wilson

B-roll of 3D imaging and Dr. Anderson