Pope Leo was diagnosed with lung cancer after surgeonsremoved a part of his right lung on Tuesday, the Vatican said in a medicalbulletin, marking a significant health setback for the 71-year-old pontiff.

The pope has lung adenocarcinoma, a common form of cancer,with tissue ‌tests conducted during the operation confirming what doctors hadsuspected from preparatory examinations, the bulletin said.

Leo was admitted to Rome’s Gemelli hospital on Tuesday forsurgery to remove the growth that doctors had discovered in a recent routinehealth check.

The pope’s lead surgeon, Dr. Stefano Margaritora, and hispersonal physician, Dr. Luigi Carbone, said in a statement that the procedurelasted about 90 minutes and was successful, with no complications.

“In order to make the procedure curative, the lower lobe ofthe right lung was removed using a video-assisted technique,” they said, makingclear that the aim was to eliminate all cancerous tissue.

Human lungs have five lobes — three in the right lung andtwo in the left.

A medical expert said that in ⁠order to assess the pope’s casethey would need to know the size of the tumour and whether the cancer hadspread to his lymph nodes, information the Vatican did not immediately provide.

“While we have the diagnosis, we do not yet have the stage.This is critical to prognosis and treatment,” said Dr. Stephen Liu, a lungcancer expert at Georgetown University in Washington and division chief ofhematology-oncology at MedStar Georgetown University Hospital.

“If this is a small lung cancer with no lymph nodesinvolved, surgery itself is likely to be curative,” he told Reuters. “But iffinal analysis reveals a greater extent of cancer involvement, this indicates apoorer prognosis.”

Resting in his hospital room

The pope regained consciousness normally after the operationand later returned to his hospital room, where he was resting, the medicalbulletin said.

The Vatican said earlier this week that he was expected toremain in hospital for about a week and all his public events have beencancelled until October 20.

Leo left the Vatican ahead of the surgery shortly before 1p.m. (1100 GMT) in Rome and was seen waving from the back of ‌a black ⁠SUVas his convoy drove about 9 km (5.6 miles) north of the Vatican to the Gemelli.

Upon arrival at the hospital, Leo shook hands with severalofficials, walked in front of a waiting crowd of well-wishers, some of whomshouted ‘Auguri’ (best wishes), and headed in via the main entrance.

Leo, elected by the world’s cardinals in May 2025, isrelatively young for a Church leader. He enjoys sports, including tennis, andis not known to be a smoker or to have had recent health issues.

The late Pope Francis, Leo’s predecessor, was hospitalisedseveral times as he grew frail in his later years. He died aged ⁠88in April 2025.

Leo, who spoke in a firm, clear voice at his only publicevent on Monday, keeps a very busy schedule. He is due to make an 11-day tourof Uruguay, Argentina and Peru from November 6 to 17, but it was not clear ifthis trip would still go ahead.

Typhoid fever

The pope is the ultimate earthly authority for the world’s1.4 billion Catholics and does not have a ⁠deputy who steps in when he issick. When a pope is incapacitated, the business of the Vatican’s vastbureaucracy carries on as usual, holding off on any decisions that requirepapal approval.

Leo, born in Chicago in 1955 as Robert Prevost, served fordecades as a missionary and bishop in Peru before becoming pope. In 1985, whenhe was a young priest, ⁠he came down with typhoid feverin Chulucanas, Peru and was hospitalised.

He recounted the experience in his only major interviewgiven as pope, in a book for Penguin Peru.

Leo said the pain was so bad that he asked God to die ratherthan continue suffering. He took his survival as a sign from God that “We needyou here (on Earth),” he said.

“I never looked back,” said Leo.