Pope Leo XIV led the Angelus prayer at the Vatican on Sunday, a day after leaving Rome's Gemelli hospital, the Associated Press reported. He left the hospital on Saturday and returned to the Vatican, four days after surgery to remove a cancerous tumor from his right lung, CBS News and the National Catholic Reporter reported.

The 71-year-old pope had initially been expected to stay in the hospital until October 20, CBS News reported, and the National Catholic Reporter reported that his schedule had been cleared through that date. His doctors said he was fit to be discharged after blood tests and a chest X-ray on Saturday, CBS News and the National Catholic Reporter reported.

Leo walked out of the hospital shortly after 3:30 p.m. local time (9:30 a.m. ET), smiling and greeting the crowds outside, the National Catholic Reporter reported. His motorcade reached the Vatican at 3:43 p.m. local time (9:43 a.m. ET), CBS News reported.

On Sunday, Leo appeared at the window of the Apostolic Palace over Saint Peter's Square to lead the Angelus, the Associated Press reported, as the Vatican's own account shows. "Now that this delicate phase is behind me, I will gradually resume my activities, always with God's help and your prayers," Leo said, according to the AP. He also thanked the doctors, nurses and staff at Gemelli hospital, the AP reported.

During the October 13 operation, doctors removed the lower part of his right lung, where a malignant tumor was found, the National Catholic Reporter reported. No information about his prognosis has been released, CBS News reported. Further tests are needed to see whether the cancer had spread to his lymph nodes, and the Vatican has not disclosed their status, the National Catholic Reporter reported.

Dr. Alexis Chidi, a thoracic surgeon at Memorial Sloan Kettering Cancer Center in New York, said her patients who have the same procedure usually stay in the hospital two to four days, the National Catholic Reporter reported. She said it can take six to eight weeks before they truly feel like themselves again.

A papal trip to South America planned for early November has been in question since his hospital stay, CBS News and the National Catholic Reporter reported. His surgeon, Dr. Stefano Margaritora, said there is no clinical reason for the pope to skip it, CBS News reported, citing an interview with Vatican News. The Vatican on Friday published the list of journalists accredited for the trip.

What we know: Pope Leo left the hospital Saturday, earlier than planned, led the Sunday Angelus and said he would gradually resume his activities.
What we don't: His prognosis, whether the cancer has spread and whether his South America trip will go ahead.