Pope Leo diagnosed with lung cancer after surgery

Pope Leo XIV is recovering after surgery on Oct. 13, which resulted in a diagnosis of lung cancer.

The pope underwent surgery to remove a small lung nodule on Tuesday that doctors had discovered in a recent health checkup. It marks the first significant medical procedure of the 71-year-old's papacy.

The Vatican announced that afternoon that the surgery was "completed successfully" and without complication, and that the pope "woke up normally and, after a brief period of observation, returned to his room on the tenth floor."

During the procedure, a team at the Agostino Gemelli University Hospital led by Professor Stefano Margaritora discovered a lung adenocarcinoma, the most common type of non-small-cell lung cancer. The lower lobe of the pope's right lung was removed, according to a statement from the Vatican.

The statement said that the tissue tests confirmed what had been indicated by pre-operation tests. The Vatican said previously that the pope was expected to spend a week in the hospital recovering.

USA TODAY reached out to the Vatican for further comment.

The pope is the ultimate earthly authority for the world's 1.4 billion Catholics and does not have a deputy who steps in when he is sick. All of Leo's public events have been canceled through Oct. 20. He is scheduled for an 11-day tour of Uruguay, Argentina and Peru starting Nov. 6.

Dr. Diego Avella-Patiño of the Sylvester Comprehensive Cancer Center, part of the University of Miami Health System, told USA TODAY in an interview that patients usually recover from the surgery in about two to three weeks, though progress can depend on the patient's overall health.

What was Pope Leo diagnosed with?

Adenocarcinoma is the most common type of lung cancer, according to Harvard Medical School. It is a type of cancer that forms in glandular cells, according to the Lung Cancer Institute of America.

While it is generally found in smokers, it is the most common type of lung cancer in nonsmokers, according to Harvard. Leo is not known to be a smoker or to have had recent health issues.

It is more likely to be found before it spreads than other lung cancers, as it tends to grow more slowly, according to the Lung Cancer Institute of America. It may respond to treatment better than other lung cancers if it is localized, according to Harvard.

Prognosis is based on the cancer's stage, the ability to identify specific mutations of the cancer cells for targeted therapy, and the patient's overall health, according to Harvard.

The bulletin did not state what stage Pope Leo's cancer was in or if it was localized.

Avella-Patiño said that the tests would return results in about seven days if the procedure had taken place in the United States. He noted that the removal of the lung indicated that doctors believed that the cancer was in an early stage.

Dr. Stephen Liu, a lung cancer expert at Georgetown University and division chief of hematology-oncology at MedStar Georgetown University Hospital, told Reuters that the Pope's prognosis depended on the stage of the cancer when it was discovered.

"If this is a small lung cancer with no lymph nodes involved, surgery itself is likely to be curative," Liu said. "But if final analysis reveals a greater extent of cancer involvement, this indicates a poorer prognosis."

Contributing: Terry Moseley and Jay Stahl, USA TODAY; Reuters