Pope Leo diagnosed with lung cancer after right lobe surgery

Pope Leo XIV was diagnosed with lung cancer during surgery on Tuesday to remove a nodular lesion from his right lung, the Vatican said in a medical bulletin. The 71-year-old pontiff has lung adenocarcinoma, a common form of lung cancer. The lower lobe of his right lung was removed using a video-assisted technique. The operation lasted about 90 minutes, and the pope spent about three hours in the operating room at Rome's Gemelli hospital.en.mercopress.com+1

The diagnosis matters because Leo leads the world's 1.4 billion Catholics and has no deputy who steps in when he is sick. What is new is that the cancer was confirmed during the operation itself, not after, and that the Vatican disclosed it publicly. The bulletin described the surgery as successful with no complications, but did not give the cancer's stage or say whether it had spread, leaving his prognosis open.independent.co.uk

What the Vatican bulletin said

The Vatican's bulletin said a rapid intraoperative histological examination, a laboratory check of tissue taken during the operation, confirmed the diagnosis of pulmonary adenocarcinoma, as suspected from pre-operative tests. Professor Stefano Margaritora, Gemelli's chief thoracic surgeon who led the team, said the lower lobe was removed "in order to make the procedure curative." Leo regained consciousness normally and was taken back to his room on the 10th floor.jpost.com

The Vatican said the aim of removing the entire lower lobe was to eliminate all cancerous tissue. Human lungs have five lobes — three in the right lung and two in the left. Leo left the Vatican shortly before 1 p.m. (1100 GMT) and his convoy drove about 9 km (5.6 miles) north to the Gemelli, where he waved to well-wishers and shook hands with officials before entering through the main entrance.

What remains unknown is the cancer's stage, which doctors say is critical to prognosis and treatment. Dr. Stephen Liu, a lung cancer expert at Georgetown University and division chief of hematology-oncology at MedStar Georgetown University Hospital, said the size of the removed tumour and whether cancer had spread to lymph nodes were both needed. "While we have the diagnosis, we do not yet have the stage," he said. "If this is a small lung cancer with no lymph nodes involved, surgery itself is likely to be curative."

What remains unknown about stage

A Vatican source quoted by the AFP news agency said further tests were being carried out to determine whether there were signs the cancer had spread. Before the procedure, oncologists said Leo's prognosis was "excellent" because any growth would be removed at an early stage. Leo announced the nodule himself on Sunday after the Angelus prayer, saying it had been found "at a very early stage" and was "well localised."

Fewer than 5% of lung nodules turn out to be cancer, according to the American Thoracic Society, and a nodule usually measures less than a half-inch. Lung adenocarcinoma makes up about 40% of all diagnosed lung cancers in the United States and forms in glandular cells on the outer parts of the lung, according to the Lung Cancer Foundation of America. It spreads more slowly than other lung cancers and is likely to be diagnosed earlier.

The Vatican has cancelled all of Leo's audiences through 20 October, and said he was expected to recover in hospital for about a week. Cardinal Pietro Parolin, the Vatican's Secretary of State, said: "Am I worried? Yes, because I certainly wasn't expecting anything like this," and highlighted the pontiff's "serenity." Candida Moss, the Edward Cadbury professor of theology at the University of Birmingham, said Vatican protocol calls for cardinals and aides to take up many of his duties as needed.

What happens next for the pope

Leo's brother Louis Prevost, who lives in Florida, fell out of remission from multiple myeloma three months ago and is in a clinical trial, his wife Deborah Prevost said. Louis Prevost was first diagnosed in 2017 and was treated in 2019. Deborah Prevost said her husband and the pope spoke last week, and that Leo called to tell them what would be happening.

Leo, born Robert Prevost in Chicago in 1955, was elected pope in May 2025 and has been active and healthy, playing tennis weekly and swimming. It is the first serious health problem publicly disclosed since his papacy began. His predecessor, Pope Francis, died aged 88 in April 2025 after several hospitalisations. Leo's public events are cancelled until 20 October, and the South America tour remains on the calendar from 6 November.