Pope Leo XIV has undergone successful planned surgery at Rome's Gemelli Hospital, during which doctors removed the lower lobe of his right lung, the Holy See Press Office says.

Pope Leo underwent thoracic surgery at the hospital on Oct. 13, Dr. Luigi Carbone and Professor Stefano Margaritora said in a release from the Holy See and the pontiff is expected to stay in the hospital for one week.

"The surgeons removed the lower lobe of the Pope's right lung.'To ensure a radical resection, the lower lobe of the right lung was removed using a video-assisted technique," the statement said.

The Pope was in the operating room for around three hours, while the operation itself lasted about 90 minutes.

"The doctors said it was successful and there were no complications," said the Holy See.

Tissue examined during the operation confirmed the diagnosis suspected from tests conducted beforehand.

"An intraoperative histological examination confirmed the diagnosis of lung adenocarcinoma, as suspected from the preoperative examinations," the doctors said.

Pope Leo awoke normally after surgery and, after a brief observation period, returned to his room on the hospital's 10th floor, according to the statement.

Professor Margaritora led the surgical team, assisted by Professor Elisa Meacci, Dr. Maria Teresa Congedo, and Dr. Leonardo Petracca Ciavarella.

The anaesthesia team comprised Professor Massimo Antonelli, Dr Giovanni Punzo, and Dr Giuseppe Bello.

In the next few days, the team will conduct post-operation exams on the removed tissue.

The Vatican said that the Pope is expected to remain in hospital for one week.

Leo held all his scheduled audiences the day before the operation.

The Vatican Secretary of State, Cardinal Pietro Parolin, said: "I am concerned because I certainly did not expect something like this to happen."

However, he noted that it was a condition "which, thank God, was detected immediately" and which could therefore be addressed "as soon as possible."

"Normally, when these things are caught in time, they can be resolved," he explained.

At 71 years old, Leo is relatively young for a pope – and remains physically active, NPR reported.

He works out weekly, including regular tennis matches with his personal secretary and enjoys riding horses at Castel Gandolfo, the papal retreat.