Pope Leo has been diagnosed with lung cancer and underwent surgery to remove a growth from his lung, the Vatican confirmed Tuesday. The 71-year-old American-born pontiff revealed Sunday at St. Peter’s Square that doctors had recently discovered a nodule in his lung, which was detected at a very early stage.

According to the Vatican, the surgery took place as planned and was successful, with Pope Leo expected to recover in the hospital for about a week. The operation marks the first major health event of his 17-month papacy. The Vatican press office stated there were no specific symptoms or incidents that led to the medical tests—contrary to some media reports—and emphasized that the tests were routine.

On Monday, the day before his hospital admission, Pope Leo maintained a full schedule, presiding over audiences and meetings, and speaking in a strong, clear voice. He also signed a letter to the outgoing dean of the College of Cardinals and participated in a weeklong conference on ministering to families, as reported by Fox 8 Cleveland and Capitol City Now.

Pope Leo’s decision to publicly share details of his diagnosis and surgery during his Sunday blessing in front of thousands in St. Peter’s Square reflects what observers describe as an unusual level of transparency for the Vatican. Historically, the Vatican has closely guarded information about the pope’s health, but Leo followed the example of his predecessor, Pope Francis, in being more open about medical issues, according to KAGS News.

Medical experts say early detection and removal of the lung nodule means the pope’s prognosis is excellent. A lung nodule is a small, abnormal area in the lung, often detected through scans for unrelated conditions. While such nodules can be benign or cancerous, surgery is commonly performed at this stage to ensure the best outcomes.

The Vatican reports Pope Leo will remain under observation as he recovers and will not immediately return to his regular public duties. The family conference he convened at the Vatican will delay its final report until after his recovery.

Simon Conway