Pope Leo has been diagnosed with lung adenocarcinoma after surgeons removed the lower lobe of his right lung, the Vatican said, marking a significant health setback for the 71-year-old pontiff.
Tissue tests conducted during Tuesday’s operation confirmed the diagnosis, which doctors had suspected following preliminary examinations of a growth discovered during a recent routine health check. The surgery took place at Rome’s Gemelli hospital and lasted about 90 minutes, according to a statement from the pope’s lead surgeon, Dr Stefano Margaritora, and personal physician, Dr Luigi Carbone.
The procedure was successful and was completed without complications, the doctors said. They removed the lower lobe of the right lung using a video-assisted surgical technique, with the aim of eliminating all cancerous tissue.
The Vatican did not immediately disclose the size of the tumour or whether the cancer had spread to the lymph nodes, two factors that specialists say are essential to determining the disease’s stage, prognosis and further treatment.
“While we have the diagnosis, we do not yet have the stage. This is critical to prognosis and treatment,” said Dr Stephen Liu, a lung cancer specialist at Georgetown University in Washington and division chief of haematology-oncology at MedStar Georgetown University Hospital.
“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.”
Lung adenocarcinoma is a common form of lung cancer. Its outlook varies considerably depending on the extent of the disease and whether it has spread beyond the original tumour. The Vatican’s announcement did not provide sufficient information to establish the stage of Leo’s cancer or whether he would require additional treatment.
The pope regained consciousness normally after surgery and returned to his hospital room to rest, the Vatican said. He was expected to remain in hospital for approximately a week, while all his public engagements had been cancelled until 20 October.
Leo left the Vatican shortly before 1pm on Tuesday, travelling about nine kilometres north to Gemelli hospital in a black sports utility vehicle. He waved to onlookers from the back of the vehicle. On arriving at the hospital, he shook hands with officials and walked past a crowd of well-wishers who had gathered at the entrance, some calling out words of encouragement.
The diagnosis raises questions about the pope’s demanding schedule and upcoming overseas commitments. Leo is due to undertake an 11-day tour of Uruguay, Argentina and Peru from 6 to 17 November, although the Vatican had not indicated whether the trip would proceed as planned.
Elected by the world’s cardinals in May 2025, Leo is relatively young compared with several recent leaders of the Catholic Church. Born Robert Prevost in Chicago in 1955, he spent decades as a missionary and bishop in Peru before becoming pope. He is known to enjoy sports, including tennis, and has not been publicly identified as a smoker.
His predecessor, Pope Francis, experienced repeated hospitalisations as his health deteriorated in his later years. Francis died aged 88 in April 2025.
Leo has previously spoken about a serious illness early in his priesthood. In 1985, while serving in Chulucanas, Peru, he contracted typhoid fever and required hospital treatment. Recalling the experience in his only major interview as pope, published in a book by Penguin Peru, he said the pain had become so severe that he asked God to let him die rather than continue suffering.
He later interpreted his survival as a sign that he still had work to do, recalling the message as: “We need you here (on Earth).”
“I never looked back,” he said.
The pope occupies the highest position of authority in the Catholic Church, which has about 1.4 billion members worldwide. There is no deputy who automatically assumes his responsibilities when he is ill. The Vatican’s administrative machinery continues to function during a pope’s incapacity, while decisions requiring his personal approval are deferred.
