Pope Leo’s Cancer Diagnosis Puts His Powerful Pontificate in Question — and Raises Specter of Papal Succession

The removal of a large section of Pope Leo XIV’s cancer-stricken lung renders his pontificate fragile just as the Bishop of Rome was emerging as a force on the world stage. On Tuesday the 71-year-old Vicar of Christ was diagnosed with lung adenocarcinoma following 90-minute surgery to remove a lower lobe of his right lung. The pontiff’s doctors at Gemelli Hospital, Dr. Luigi Carbone and Professor Stefano Margaritora, say that their patient is recovering as “expected” after the surgery was performed “using a video-assisted technique.” The Vatican has cancelled all audiences until October 20.The course of that recovery, though, collides with what was expected to be an early centerpiece of his pontificate — a trip next month to South America that is meant to include stops in Uruguay, Argentina, and Peru. The last of those holds a special place for Pope Leo, who spent 20 years as a priest in the country, earning citizenship and eventually serving as the Bishop of Chiclayo. The pope has just returned from what was roundly hailed as a triumphant trip to France, which included a Mass attended by 800,000 along the Avenue des Champs-Élysées. Another 75,000 people attended a prayer vigil he led at the Stade de Paris. The crowds in South America were expected to number in the millions. The planned journey to Buenos Aires is freighted with significance given that Pope Francis never returned as pontiff to his homeland. The Vatican insists that the trip will proceed as planned. Secretary of State Marco Rubio, a Catholic, writes in respect of the Bishop of Rome, “May the Lord give him strength and the Holy Spirit guide the medical professionals taking care of the Holy Father.” Pope Leo’s mother and father both died from cancer, and his brother has been afflicted by the disease as well.Pope Leo XIV at St Peter’s Basilica on October 08, 2026 at Vatican City. Vatican Media via Vatican Pool/Getty ImagesThe Centers for Disease Control and Prevention estimates that the variety of lung cancer with which the pope was diagnosed is treatable if caught early, as it appears to have been here. The second-ranking figure at the Holy See after the Vicar of Christ is the Vatican’s secretary of state, Pietro Cardinal Parolin. A powerful prince of the Church, he has served in that role since his appointment by Francis in 2013. Pope Leo’s diagnosis, which the BBC calls “seismic,” comes 17 months after white smoke snaked over the Sistine Chapel to signal that the College of Cardinals — with, the faithful say, a helping hand by the Holy Spirit — had selected the successor to Francis and Saint Peter. Francis was handed the Fisherman’s Ring after his predecessor, Pope Benedict XVI, retired to the role of Pope Emeritus. No Bishop of Rome had resigned in 600 years. The first American pope has rapidly emerged as a force on the global stage. He clashed with President Trump over the war with Iran, denying that the conflict is a “just war.” The pope also called the president’s language “truly unacceptable” and has criticized the Trump administration’s stance on immigration. The president has called the pope “weak on crime,” and “terrible for foreign policy.” Pope Leo has also come out against America’s plan to execute, via livestreamed firing squad, the terrorist Nidal Hasan.So opposed is the Vatican to the death penalty that earlier this week the Archbishop for the Military Services, Timothy Broglio, declared in a statement that Rome commands that “any Catholics assigned to the firing squad” for the execution of Hasan must “request to be excused from this action contrary to the teaching of the Church.” Vice President Vance, a Catholic convert, does not plan to watch the execution, though he supports it.Pope Leo has also emerged as one of the globe’s most prominent voices on artificial intelligence. His first encyclical, published in May, is entitled “Magnifica humanitas.” It is devoted to the task of “safeguarding the human person in the time of artificial intelligence.” Unlike most pontiffs, he presented the document himself rather than delegate that task to a radiance of cardinals. The pope has also decried the rise of AI-generated art and warned of the encroaching dystopia of a “paradise of the machines.”If Pope Leo’s pontificate is cut short, jockeying between the Vatican’s conservative and liberal factions is likely to immediately ensue. That tension has been another defining feature of this pontificate, most explosively with the schismatic traditionalist group, Society of Saint Pius X, whom Pope Leo excommunicated in July after the society insisted on consecrating its own bishops despite the Vatican’s explicit prohibition.Pope Leo has also not repealed the 2021 restrictions on the Traditional Latin Mass instituted by Pope Francis, though he has allowed for the possibility of congregations applying for permission to worship in the “Extraordinary Form,” which was instituted by Pope Pius V in 1570. This balancing act suggests that the pope is seeking a middle way between his two immediate predecessors — the doctrinally liberal Francis and the arch-conservative Benedict.If the pope’s reign ends, the College of Cardinals would again convene beneath Michelangelo’s Sistine ceiling to elect a new pope. Some of the papabili, or top contenders, at the last conclave were Cardinal Parolin, the more liberal Luis Antonio Cardinal Tagle, and two conservatives, Péter Cardinal Erdő and Robert Cardinal Sarah.

Pope Leo’s Cancer Diagnosis Puts His Powerful Pontificate in Question — and Raises Specter of Papal Succession

Pope Leo’s Cancer Diagnosis Puts His Powerful Pontificate in Question — and Raises Specter of Papal Succession

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