Shape of Pope Leo's papacy more uncertain after cancer diagnosis - Reuters

When U.S. Cardinal Robert Prevost was elected Pope Leo XIV in May 2025, he presented a markedly different image from his predecessor, Pope Francis. At 69 years old, Leo was the first U.S.-born pontiff, appeared energetic, spoke with a strong voice and had no known health problems, contrasting with Francis, who died at 88 after a period of frailty.

On 13 October, the Vatican announced that Pope Leo, now 71, had been diagnosed with lung cancer after surgeons removed part of his right lung that afternoon. The diagnosis was made public following the operation, and the Pope’s condition has become a focal point for the world’s 1.4 billion Catholics.

Medical experts note that the Pope’s prognosis will depend on several factors, including whether the cancer has spread to his lymph nodes, a detail that has not yet been disclosed. The uncertainty surrounding the disease means that the future shape of his papacy—once expected to involve numerous foreign trips and a prominent moral voice on the global stage—cannot be definitively projected at this stage.

John Thavis, a Vatican scholar and author, said it is too early to determine how the illness will affect Pope Leo’s agenda or his ability to carry out the duties of the papacy. He emphasized that the impact will hinge on the cancer’s progression and the success of ongoing treatment.

Since his election, Pope Leo has become an increasingly influential figure beyond the Church, warning about the risks of artificial intelligence and drawing criticism from U.S. President Donald Trump after condemning the war in Iran. The recent health development adds a new layer of uncertainty to how long he will be able to pursue these initiatives.