Why do non-smokers get lung cancer?

The Vatican's recent announcement that Pope Leo XIV, the 71-year-old leader of the Catholic Church, has lung cancer was a surprise and shock to many around the world, especially since he reportedly does not have a history of smoking.

The Pontiff had surgery to remove a lung nodule (a small, round or oval shaped abnormal growth) and the lower lobe of his right lung on October 13. Previous testing had indicated it as adenocarcinoma and was confirmed by tissue samples taken and tested during the surgery.

Adenocarcinoma is a type of non-small cell lung cancer that begins in the cells that line the small air sacs of the lungs and make mucus. It occurs in 50-60 percent of non-smokers diagnosed with lung cancer, according to the Centers for Disease Control and Prevention (CDC).

"The Pope had a lobectomy, which tells me he had an obvious cancer and the big determinant was that the lymph nodes were not involved," said Jeffrey Spillane, MD, FACS, a general and thoracic surgeon with Cape Cod General and Thoracic Surgery in Hyannis. "If the lymph nodes aren't involved and the nodule was a smaller lesion - like 2 centimeters, which is less that one inch, the treatment is surgery alone."

Smoking is the leading cause of lung cancer, according to the American Lung Association. But, according to a Facebook video post in which he described the Pope's cancer and surgery, infectious disease specialist and member of the Catholic Medical Association Robert Tibilli, DO, said the Pope did not have a history of smoking.

Risk Factors

Genetics may have played a part in Pope Leo's disease, said Dr. Spillane.

"Some people may have more, or some may have less of a genetic component, but cigarettes are a clear accelerant, along with other irritants that may unleash that genetic risk earlier in life than if you didn't smoke," he said.

In addition to genetics, other risk factors for non-smokers include:

• Exposure to other people's smoking (secondhand smoke).
• Radon.
• Air pollution.
• Asbestos.

There are currently no lung cancer screening guidelines for nonsmokers, Dr. Spillane said.

Announcements from the Vatican noted the Pope had no symptoms and the nodule was an "incidental" finding as a result of testing for an unrelated condition.

An incidental finding is a nodule or abnormality discovered during imaging tests (such as CT scan or MRI) performed for an unrelated reason.

"We are seeing a rise in non-smoking patients with lung cancer found as an incidental finding because we are doing more CT scans to check for other medical conditions," said Dr. Spillane.

Follow-Up is Key

Any nodule or mass that is found incidentally during imaging for unrelated conditions at Cape Cod Hospital or Falmouth Hospital is automatically reviewed by Dr. Spillane and his team.

"My team and I have a nodule conference every week," he said. "We are alerted to any scan results on the Cape that have an L-RAD rating of three or four, and we review the scan and findings as a group to see if it could be pneumonia or another pulmonary condition. It the area looks suspicious, we will contact the patient's primary care physician or sometimes we will contact the patient directly and recommend further tests."

L-RAD is a set of assessment categories established by the American College of Radiology to categorize lung nodules and findings into specific numbers and letters, which helps determine the level of concern and course of action.

A level 3 category means it is probably benign with a recommended short-term follow-up and includes nodules with low likelihood of becoming cancer. Category 4 is considered suspicious with additional diagnostic testing recommended.

"A large part of my job is talking with patients to explain their diagnosis and reassure them at the same time," said Dr. Spillane.