Pope Leo XIV is preparing to undergo surgery to remove a localised nodule in his lung, which was detected at a very early stage. The procedure is the first reported medical event of his 17-month papacy.The 71-year-old pontiff is otherwise considered healthy and physically fit. Here is a look at what is known about the lung nodule, his planned treatment, the possible impact on his engagements and the question of papal authority during a medical emergency.

What is a lung nodule? Can it be cancerous?

A lung nodule is a small abnormal spot in the lung measuring less than 3 centimetres (approximately 1.2 inches) in diameter. According to the american cancer society, such nodules are sometimes discovered during CT scans carried out to investigate other conditions, including injuries or lung infections.Lung nodules may be benign or malignant, making timely medical assessment important to establish their nature.Dr Stephen Liu, a lung cancer specialist at Georgetown's Lombardi comprehensive cancer center, said the prognosis is “excellent” when a cancerous nodule is detected and removed at an early stage. In some cases, surgery alone may be enough to treat the condition.Leo said the nodule was identified during “recent medical tests”.

The Vatican said on Monday that the check-up was “routine” and had not been prompted by any specific health concern.

Surgery planned, followed by a week of recovery

The Vatican announced that Leo would undergo the procedure during the first days of the week. He is expected to remain in hospital for around a week to recover.The pope will receive treatment at Rome's Gemelli Hospital, officially known as the Agostino Gemelli Polyclinic. The private, non-profit catholic teaching hospital has a dedicated apartment for pontiffs on its 10th floor, which includes a private chapel.Leo's predecessor, Pope Francis, was treated at the same hospital before his death in May 2025 following a prolonged illness that included a respiratory crisis.St John Paul II also spent considerable time at Gemelli and famously referred to it as “Vatican III”, alongside the Vatican itself and the papal summer residence at Castel Gandolfo.Will the procedure affect Leo's schedule and foreign trip?The pope has several engagements lined up for the week, including his regular meetings and a public mass scheduled for Wednesday.

The mass is due to mark the end of a weeklong conference on family ministry, but Vatican officials indicated on Sunday that Leo might not attend.His planned overseas visit from November 6 to 17 to Uruguay, Argentina and Peru could also be affected by the operation and recovery period.The itinerary involves 12 flights, two helicopter journeys and considerable changes in altitude during the Peru leg. It remains uncertain whether the medical procedure will require any changes to the schedule.According to the Leo, he is still intended to undertake the trip, stated during the Sunday.

Does the pope retain authority while unconscious?

The Vatican has no specific rules determining, who assumes a pope's powers if he becomes completely incapacitated. As a result, Leo would remain pope and retain his authority even while unconscious during surgery.Previous pontiffs continued to exercise their responsibilities during extended hospital stays. Pope Francis and St John Paul II made appointments and issued laws and statements while undergoing treatment.The Vatican's day-to-day affairs are already managed by a team of officials, but the absence of a formal framework for a pope, who becomes unable to govern has attracted increasing attention.Advances in medical treatment and longer life expectancies have intensified calls for the church to establish clearer arrangements for a pontiff who becomes seriously ill or incapacitated for an extended period.

Cardinal Tagle appointed dean ahead of surgery

Two days before announcing his planned operation, Leo approved an important appointment within the church's leadership.On Friday, he named Filipino Cardinal Luis Antonio Tagle, 69, as the new dean of the College of Cardinals. Tagle succeeds Cardinal Giovanni Battista Re, 92, whose term had been extended by Pope Francis in the weeks leading up to his death.The dean plays a key role during the transition between popes. The position involves presiding over the previous pontiff's funeral and helping lead closed-door meetings of cardinals ahead of the conclave, where they discuss the church's priorities and future direction.If the dean is younger than 80, when the conclave begins, he also presides over the secret election of the next pope in the Sistine Chapel.