Pope's lung cancer is a reminder that nonsmokers can be at risk. What to know

SALT LAKE CITY — Pope Leo XIV's lung cancer diagnosis and surgery are good reminders that even those who never smoked can get lung cancer, too.

On Oct. 16, Dr. John Stringham, a thoracic and oncology surgeon for Intermountain Health, briefed members of the news media on other risk factors.

The American Cancer Society estimates that just under 125,000 people die from lung cancer each year in the U.S., including smokers, former smokers and people who never smoked. While smoking is still responsible for most cases, between 15% and 20% of lung cancer cases are found in people who have never smoked, according to a 2025 JAMA study.

The pope's cancer, which was pulmonary adenocarcinoma — a common form of non-small cell lung cancer — was found at the early stage and biopsied during surgery, so those treating him said they were able to remove the lower lobe of his right lung.

It's likely the surgeon removed nearby lymph nodes to make sure it hadn't spread, as well, said Stringham, who was not involved in the pope's treatment. He said reports suggest that surgery is likely the only treatment he will need. When cancer has spread to lymph nodes, "then we usually do talk about chemotherapy, sometimes radiation for those folks."

In cases where the cancer is contained, Stringham said there's an estimated 80% to 90% cancer-specific survival rate at five years. When lung cancer has metastasized, which means it has spread to other parts of the body, the survival rate at the five-year benchmark drops.

Stringham also noted that the pontiff, who is 71, is physically active and known to swim and play tennis. "Most likely he's going to have a good recovery if everything goes according to plan," though he'll be monitored. "Most likely he'll be going through CT scans for at least five years to make sure nothing comes back," the doctor said.

Detected early, the recurrence rate is "actually pretty low," he said. And those patients "recover from lung cancer surgery pretty well and pretty easily. I definitely have had patients where we take out a lower lobe and they have gone on to do marathons, for example."

About lung cancer and risks

But there's a lot to know about lung cancer, which often is not diagnosed until it is much more advanced than that of the pope. Early cases are usually detected — as they were in his case — through an imaging test for something else.

Lung cancer is the leading cause of cancer death in the world, including in the U.S.

Stringham said lung cancer is divided into two categories: small cell and non-small cell. Small cell lung cancers are more aggressive and spread more quickly, while non-small cell cancers are most typical and also more treatable.

The two main types of non-small cell are squamous-cell carcinoma and adenocarcinoma — Pope Leo's diagnosis — which is the most common among nonsmokers with lung cancer. Early-stage non-small cell lung cancers are typically treated with surgery as the mainstay, he said. A lobe is removed. If it had spread, there are other treatments that are "becoming more and more effective" due to better technology and better understanding of cancer. It's possible to look at the actual molecules cancers are expressing and use those molecules against them with immunotherapy, among other options.

"If you are smoking now, please stop," Stringham said, noting doctors have tools to help smokers quit. "Even stopping right now is going to help out so much" in reducing risk of lung cancer in the future.

He recommends "not putting things in your lungs that shouldn't be there."

But there are other much less obvious risks for the disease, he said, including "secondhand smoke, any kind of occupational exposure to things you might find on the job like solvents, chemicals, those sorts of things." He noted that mining and industrial jobs that have people breathing in dust or solvents, for example, could lead to lung cancer. Anyone exposed to that type of risk should wear a respirator and keep the area well ventilated.

Radon, a radioactive noble gas in the soil that is colorless, odorless and tasteless, "is definitely a risk factor. We have radon in the soil and we do have folks with radon in their basements, for example, so we always encourage folks to get their basement tested for radon," which can be mitigated to reduce the likelihood of developing lung cancer from it.

The Environmental Protection Agency estimates that radon gas causes about 21,000 lung cancer deaths each year. And radon experts note that testing is not a one-and-done, but should be conducted periodically.

Stringham said pollution is also a big concern. Pollution levels and the duration of exposure all impact the risk and the Wasatch Front with its inversions is not immune. "Obviously, trying to keep our air as clean as possible is a good thing to do," said Stringham.

There are also genetic factors for lung cancer, including inherited mutations that pass down through the family.

Vaping is also considered a risk for lung cancer, he said, but less is known about smoking marijuana or vaping than about smoking. Stringham said exposure to the chemicals, smoke and particulates in cigarettes over time, and the amount that folks smoke, is probably what causes a higher estimated risk compared to marijuana or vaping.

As for prevention, there's not much to do but mitigate risks by wearing respiratory protection when working around pollutants, chemicals and irritants and keeping the area well ventilated. And take care of yourself: exercise, eating well, seeing a doctor and other typical well-being advice all help ensure a person is as healthy as possible.

Detection and prevention

One of the challenges with lung cancer is that symptoms don't really show up early. "Very often, lung cancer really doesn't have any symptoms whatsoever," according to Stringham, who noted maybe a cough sometimes or some sputum production. "But often it's really quite asymptomatic until you actually get to a much higher stage when it's much bigger and causing pushing on other organs, on other things."

When lung cancer spreads, it most often goes to lymph nodes in the middle of the chest, then outwards, though not always. After that, it can go "pretty much anywhere in the body," he said, noting the spine and brain are not uncommon. Sometimes, it doesn't go to the lymph nodes but does spread elsewhere.

For folks who want to know more, Stringham recommends looking at the annual "State of Lung Cancer" report by the American Lung Association, which tracks the disease state by state.

Screening for smokers and former smokers

Lung cancer screening is now recommended for smokers and former smokers, using low-dose CT scan to make sure there are no nodules.

The U.S. Preventive Services Task Force recommends annual screening for adults ages 50–80 with at least a "20 pack-year" smoking history who currently smoke or quit within the past 15 years. That means 20 cigarettes a day for 20 years or an equivalent amount.

It's not recommended for others, who "don't qualify for it at this time." That's a matter of risk versus benefit and is why Stringham said it's vital "when we do get other imaging to really look at the lungs and make sure there aren't any other nodules in that area."

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