Louis Prevost, the eldest brother of Pope Leo XIV, spoke about the pope’s cancer diagnosis and recovery in an interview on Fox News this weekend.

“When they did the operation, they got all the cancer out,” Mr. Prevost explained, referring to the pope’s surgery on Oct. 13 in which the lower lobe of his right lung—about one-third of the lung, where a cancerous nodule was growing—had been removed. (The Vatican has not yet confirmed whether the pope is cancer-free.)

While a test on the nodule confirmed the diagnosis of adenocarcinoma during the pope’s surgery, further biopsy tests on the removed tissue are still being conducted. Mr. Prevost said on Fox: “I don’t anticipate anything negative about that, just based on what the doctors have been saying and what they saw, but you never know. So we keep praying that the biopsy comes back completely negative and he’s all good to go.”

Mr. Prevost did not discuss any other tests the pope might have undergone to see whether cancer was present outside of the removed tissue, nor did he speak on what stage the cancer had reached. When the pope announced on Sunday, Oct. 11, that he would undergo surgery, he described the growth as being at “a very early stage.”

On Oct. 13, hours after the surgery, the pope’s doctors confirmed that Pope Leo had been diagnosed with lung adenocarcinoma, the most common type of non-small cell lung cancer. In the Fox News interview, Mr. Prevost said that, as far as he was aware, his family had no history of lung cancer, describing it as a “freak diagnosis.”

Both of the pope’s parents died of cancer, according to Cook County death records obtained by America, with the pope’s father having atherosclerotic heart disease listed as a contributing condition.

Louis Prevost, the pope’s brother who was interviewed on Fox News, was diagnosed with multiple myeloma, a type of blood cancer affecting plasma cells, in 2017 and was successfully treated in 2019, although his wife told CBS News that he “fell out of remission” about three months ago.

Mr. Prevost said that although it was “panic city” when the family first found out that Leo might have cancer, “after the day of surgery, when they reported that they got it all, it was clean and pretty straightforward.”

He said the pope’s recovery is going well and that his brother is “doing fabulously.”

The Vatican had originally predicted that the pope would recover in the hospital for a week after his surgery and canceled his audiences through Oct. 20. The pope was discharged on Saturday, Oct. 17, and prayed the Angelus and addressed crowds from his window overlooking St. Peter’s Square on Sunday, Oct. 18, as he does each week.

He is not making his usual Tuesday trip to Castel Gandolfo, instead resting in the Vatican, where, he said on Sunday, he will “gradually resume my activities.”

One key question regarding the pope’s recovery is whether he will be able to make his planned trip to South America from Nov. 6-17. The surgeon who operated on the pope, Dr. Stefano Margaritora, told Vatican News on Saturday that the pope “could be fully recovered” in another 10 days, around Oct. 27.

“As for a long trip involving air travel in about three weeks, I would say there are no clinical reasons why it should not take place,” Dr. Margaritora said. The Vatican has neither confirmed nor denied whether the visit will go forward as planned.

Speaking on Fox News, Louis Prevost said he was “quite surprised” at the surgeon’s comments, adding, “I thought maybe they’d postpone” the trip. He said he had hoped to join the pope on “at least one of the stops” on the visit to Uruguay, Argentina and Peru.

Mr. Prevost added that he had spoken to his brother daily “since this happened,” seemingly referring to the cancer diagnosis. Previously, the two spoke less often, and Leo spoke daily with their other brother, John Prevost, who lives outside Chicago.

John Prevost gave interviews about the pope frequently after the 2025 conclave before adopting a more careful approach to the media, frequently appearing alongside Augustinian Father Ray Flores in interviews. Asked by NBC Chicago whether Pope Leo had asked him to “be careful” in interviews, John Prevost said: “Yes, absolutely. That’s why this gentleman is here,” referring to Father Flores.

Louis Prevost has generally given fewer interviews but has gained attention for his vocal support of President Donald Trump, who invited him to the White House soon after the election of Pope Leo. Speaking to British broadcaster Piers Morgan in December, Mr. Prevost said he had “toned down my tweets and my Facebook posts because they always catch fire, end up on the news saying ‘The pope’s brother said,’ and the pope hears about it.” He said both of his brothers had asked him “not [to] be so vocal about things or, you know, so negative.”

Previous papal siblings have also, at times, spoken to the media. At the time of his election, Pope Francis had one living sister, María Elena Bergoglio, who famously told reporters that she had prayed her brother would not be elected pope so that he would not leave Argentina. She occasionally gave interviews during Francis’ papacy to Spanish-language outlets and contributed to a biography of Pope Francis by American journalist Deborah Castellano Lubov.

Pope Benedict XVI’s brother, Georg Ratzinger, was a famous choir director and gave interviews to Catholic and secular news outlets; he also worked with German journalist Michael Hesemann on a book-length interview entitled My Brother, The Pope.

Colleen Dulle is the Vatican Correspondent at America and co-hosts the "Inside the Vatican" podcast. She is the author of Struck Down, Not Destroyed: Keeping the Faith as a Vatican Reporter (Image, 2025).