Pope Leo was diagnosed with a common form of lung cancer after doctors removed a lower lobe of his right lung in surgery on Tuesday, the Vatican said in a medical bulletin.
The 71-year-old pontiff has lung adenocarcinoma, with tissue tests conducted during the operation confirming what doctors had suspected from preparatory examinations, the bulletin said.
The pope was admitted to Rome's Gemelli hospital on Tuesday for surgery to remove a growth on his lung that doctors found in a recent health checkup.
The Vatican had said earlier on Tuesday evening that the surgery had been successful before providing a more detailed update from the pope's lead surgeon, Professor Stefano Margaritora, the chief of thoracic surgery at the Gemelli.
"In order to make the procedure curative, the lower lobe of the right lung was removed using a video-assisted technique," said Margaritora's update.
"A rapid intraoperative histological examination confirmed the diagnosis of lung adenocarcinoma, as had been suspected from the pre-operative tests," it said.
Tuesday's surgery lasted about 90 minutes and was successful with no complications, the Vatican said. The pope has woken up normally and is resting in his hospital room.
The statement did not provide further details.
EXPECTED TO STAY IN HOSPITAL A WEEK
Leo left the Vatican ahead of the surgery shortly before 1 p.m. (1100 GMT) in Rome and was seen waving from the back of a black SUV as 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 several officials, walked in front of a waiting crowd of well-wishers, some of whom shouted 'Auguri' (best wishes), and headed in via the main entrance.
The Vatican said earlier this week that the pope was expected to recover in hospital for about a week. All his public events have been cancelled until October 20.
Leo, elected by the world's cardinals in May 2025, is relatively young for a Church leader. He enjoys sports, including tennis, and is not known to be a smoker or to have had recent health issues.
The late Pope Francis, Leo's predecessor, was hospitalised several times as he grew frail in his later years. He died aged 88 in April 2025.
Leo, who spoke in a firm, clear voice at his only public event on Monday, keeps a very busy schedule. He is due to make an 11-day tour of Uruguay, Argentina and Peru from November 6 to 17.
TYPHOID FEVER
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. When a pope is incapacitated, the business of the Vatican's vast bureaucracy carries on as usual, holding off on any decisions that require papal approval.
Leo, born in Chicago in 1955 as Robert Prevost, served for decades as a missionary and bishop in Peru before becoming pope. In 1985, when he was a young priest, he came down with typhoid fever in Chulucanas, Peru and was hospitalised.
He recounted the experience in his only major interview given as pope, in a book for Penguin Peru.
Leo said the pain was so bad that he asked God to die rather than continue suffering. He took his survival as a sign from God that "We need you here (on Earth)," he said.
"I never looked back," said Leo.