A Mount Carmel Health pulmonologist says the cancer from which Pope Leo XIV is recovering is “rare, but not uncommon.”
The Pope had surgery in Rome on Tuesday, Oct. 13 to remove the lower lobe of his right lung, using a video-assisted technique, after a spot known as a nodule was discovered there. He announced plans during his Angelus address two days earlier that the surgery would take place.
Postoperative examination confirmed that the spot, which was discovered during a routine medical checkup, was pulmonary adenocarcinoma, or lung cancer. The nodule was localized and in its very early stages of growth when it was surgically removed.
The Pope returned to the Vatican on Saturday, Oct. 17. He resumed his Wednesday general audiences on Oct. 21 and 28, gave his weekly Angelus address on Sunday, Oct. 25 and went ahead with plans to visit Uruguay, Argentina and Peru from Nov. 6 to 17.
The American Lung Association says lung nodules appear in more than one in four CAT scans, with about 1.5 million detected each year. A CAT scan combines X-ray measurements with computer processing to create cross-sectional pictures of the inside of the body.
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Most lung nodules are noncancerous but some can be an early sign of lung cancer, the leading cause of cancer-related deaths in the United States.
“Pulmonary adenocarcinoma is the most common type of lung cancer,” said Dr. Inderpal Singh Thethi, who specializes in lung diseases and is affiliated with Mount Carmel East Hospital in Columbus and Mount Carmel St. Ann’s Hospital in Westerville. He has 19 years of experience, including five with Mount Carmel Health.
“Most of those with lung cancer are smokers, but 15 to 20 percent of those with the condition do not smoke,” Thethi said. “Assuming the Pope is a nonsmoker, it’s likely that he contracted lung cancer from another source. It could be secondhand smoke, or the cause could be air pollution, asbestos or other environmental or genetic factors. Age also plays a role.” The Pope is 71 years old.
An October 2025 study published in the Journal of the American Medical Association said the annual incidence of lung cancer in nonsmoking men is 4.8 to 12.7 cases per 1,000 in the United States. “So the Pope’s situation is rare, but not uncommon,” Thethi said.
“The important thing about finding the cancerous nodule in the Pope, or for anyone, is that it was discovered early. During the checkup at which the nodule was found, I imagine his medical history was discussed and he perhaps had a chest X-ray, which is routine for someone his age, and the spot was found. He also might have been given a CAT scan to take a closer look at it.”
Thethi said surgery to remove such a spot usually occurs when it is 1 centimeter or more in diameter, with the riskiest operations occurring when it is in the upper portion of the lung rather than the center. The surgery is easiest when a nodule has smooth borders and is mostly circular in shape and is more difficult when the spot has an irregular shape with sharp, thorny edges.
The presence of calcium also can be an issue. “Calcium generally is not a concern in cases where it is in the center of the nodule but can be a problem when it’s on the edges,” he said.
The Pope’s surgery took about 90 minutes and that’s a standard length for such a procedure, Thethi said.
He said the process Pope Leo went through from discovery of the nodule through recovery was about the same as anyone else would undergo.
“The best way to prevent lung cancer, and the key to any cancer detection, is visiting the doctor regularly for checkups,” he said. “If your medical history indicates the possibility of lung cancer, particularly if you’ve had 20 pack-years of smoking (a pack a day for 20 years), the doctor might order a chest X-ray, followed possibly by a CAT scan or perhaps a PET scan, which uses radioactive tracers.
“The next step probably would be a biopsy, performed by a pulmonologist. For lung cancer, this involves making several passes with a needle to obtain tissue cells to determine whether nodules are malignant (cancerous) or benign and to determine the stage of any cancer.”
Sometimes a biopsy is sufficient to remove cancerous cells. Surgery led by a pulmonologist with an interdisciplinary tram of physicians is needed at other times, with the type of treatment depending on the stage of the cancer.
In some cases, surgery is too risky because of a person’s overall health and other factors such as age or other serious medical conditions.
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Follow-up treatment after surgery may consist of chemotherapy, using powerful drugs to destroy fast-growing cancer cells to stop them from multiplying. Another possibility is radiation, a course of five visits during which a machine uses high-energy rays to destroy cancer cells and stop them from growing and dividing.
These procedures are followed by rehabilitation at home and regularly scheduled visits with a doctor every three to six months for several years to ensure the cancer has not returned, plus occasional CAT scans of the chest and perhaps additional surgery with a multidisciplinary team of doctors.
“I can’t emphasize enough the importance of early detection,” Thethi said. “Lung cancer is completely treatable with minimal complications if it’s found early.
“See your primary physician at least once a year, but if you have shortness of breath, chest pains or night sweats or are coughing up blood, call for an appointment immediately, as these are the common signs of cancer.
“Modern medicine can do great things but it’s up to you to take the first step.”