Pope Leo XIV greets his older brother, Louis Prevost, in St. Peter's Basilica following the pope's inaugural Mass at the Vatican May 18, 2025. (CNS/Lola Gomez)
by Simone Orendain
Join the Conversation
Send your thoughts to Letters to the Editor. Learn more
While Pope Leo XIV was recovering from an Oct. 13 surgery to remove the lower lobe of his right lung where doctors found cancer, his oldest brother Louis Prevost was in a Florida hospital receiving treatment for a blood cancer that had become very active after seven years of being at a "low level."
Prevost told OSV News Oct. 16 that he and his wife, Deborah, "would be in Rome right now" with his brother otherwise.
"But we're each confined to each other's respective hospitals," he said with a chuckle.
Leo, 71, was released Oct. 17 from Rome's Gemelli hospital, four days after a successful procedure that discovered a malignant tumor in his right lung and removed its lower lobe. Doctors have said there were no complications in the procedure, but further tests are needed to determine if the cancer had spread into Leo's lymph nodes or other parts of his body. The Vatican has not disclosed the status of those tests.
Before being discharged from the hospital, Leo celebrated noon Mass at the hospital as he did the previous day, OSV News reported. On Oct. 16, Leo also called Russian President Vladimir Putin, urging a ceasefire in Russia's war with Ukraine.
On Oct. 13, CBS News reported Deborah Prevost shared with the news network that her husband has multiple myeloma. This form of cancer grows in plasma cells, which are a type of white blood cell. According to the Mayo Clinic, the cancer makes abnormal proteins that "can build up and damage organs, such as kidneys."
Prevost's cancer was diagnosed in 2017 and had been at a "very low" level of activity "for years" until three months ago, she said. The brothers spoke before Leo's surgery when the pontiff called to let them know what was happening.
"We keep praying, keeping spirits up for both of them," she told CBS News.
Louis Prevost, 75, explained to OSV News that he had entered a clinical trial in 2019 that involved the cycling of blood cells out of his body and infusing the healthy cells back in, in a process that can take seven to eight hours. He said this time, the clinical trial has become more scientifically advanced, with the side effects being less severe.
He told OSV News he has "absolutely" leaned on his faith throughout the illness.
Advertisement
"I firmly believe in the power of prayer, because when I was first diagnosed, I wasn't given much of a survival chance. And here it is, nine years later and I'm still kicking and feeling OK and still around," said Prevost.
"As much as I can, I'm fully on board with all the sacraments and the blessings of the church," he said. "And all the prayers from my own family and the messages that I get from friends and people that I have never met that say 'We're praying for you.'"
Vice President JD Vance, a Catholic, also noted that Louis Prevost was battling cancer in an Oct. 14 post on X praying for the "good health and full recovery of Pope Leo XIV." He said, "May God keep both of these brothers healthy for years to come."
Prevost told OSV News he has been seeking the intercession of St. Carlo Acutis, the first millennial saint, who died within days of being diagnosed with leukemia at 15 years old. And lately, Prevost said, he has also been asking for the newly beatified Archbishop Fulton Sheen's intercession.
Prevost said both of their parents had cancer, but that his form of cancer was not hereditary.
He said he suspected his cancer was brought on by environmental factors, such as exposure to chemicals while serving in the U.S. Navy.
Prevost said he was grateful for the prayers, but he had one request.
"I always ask people, 'Keep praying for my brother, that he makes a full recovery,' " Prevost said, "because I think he's the pope the church needs at this time."
[Simone Orendain is an OSV News correspondent. She writes from Chicago.]
