ROME, Italy — The elder brother of Pope Leo XIV is undergoing treatment for blood cancer, his wife has disclosed.
Louis Prevost, who lives in Florida, has been diagnosed with multiple myeloma, a cancer affecting plasma cells in the blood and bone marrow.
The disclosure came as the 71-year-old Pope recovered from surgery to remove a cancerous growth from his right lung at Rome’s Gemelli Hospital.
Deborah Prevost told CBS News on Tuesday, October 13, 2026, that her husband was participating in a clinical trial after his cancer returned three months earlier.
She said the family was “going through a lot” as the brothers received treatment for different forms of cancer.
“We keep praying, keeping spirits up for both of them,” she said.
Brother’s Cancer Returned After Years of Treatment
Louis Prevost was first diagnosed with multiple myeloma in 2017.
His wife said he underwent treatment in 2019, including stem cell therapy and participation in a clinical trial.
The treatment substantially reduced the disease, allowing him to maintain it at a very low level for several years.
However, his cancer returned approximately three months ago, prompting further treatment at a hospital in Florida.
Deborah did not disclose the current stage of her husband’s illness.
Multiple myeloma develops in plasma cells, a type of white blood cell found in the bone marrow.
According to the UK National Health Service, the disease can affect the bones, kidneys, and immune system.
Although multiple myeloma is generally not considered curable, treatments can control the disease for extended periods.
The Multiple Myeloma Research Foundation says advances in treatment have improved outcomes for many patients.
Louis also confirmed his diagnosis in a separate interview with the American television network Newsmax.
He said he was undergoing CAR-T cell therapy, a treatment in which a patient’s immune cells are modified to recognise and attack cancer cells.
The therapy is used to treat certain blood cancers, including multiple myeloma.
Pope Undergoes Surgery for Lung Cancer
The family’s disclosure followed the Vatican’s confirmation that Leo had undergone an operation for lung cancer.
Doctors removed the lower lobe of his right lung during a procedure at the Agostino Gemelli Polyclinic in Rome.
The operation lasted approximately 90 minutes, although the pontiff spent about three hours in the operating room.
A tissue examination conducted during surgery confirmed that he had lung adenocarcinoma, a common form of lung cancer.
The Vatican said the operation was completed without complications.
According to an official medical bulletin published by Vatican News, surgeons used a video-assisted technique to remove the affected portion of the lung.
The operation was performed by a team led by Professor Stefano Margaritora, head of thoracic surgery at Gemelli Hospital.
The Pope’s personal physician, Luigi Carbone, also participated in his care.
Doctors said the removal of the lower lobe was intended to eliminate the cancerous tissue.
Further examination of the removed tissue is expected to help establish the extent of the disease and whether additional treatment will be required.
The Vatican has not disclosed the precise stage of the cancer or confirmed whether it has spread beyond the lung.
Vatican Reports Normal Recovery
The Pope’s doctors said on Wednesday that his recovery was progressing normally.
Blood tests and a chest X-ray showed results consistent with the expected course following his operation.
The pontiff had begun walking around his hospital room, resumed eating normally, and started respiratory physiotherapy.
He also celebrated Mass with his secretaries in a chapel prepared inside the hospital.
In a further Vatican medical update, doctors said the findings showed no unexpected complications.
The Pope is expected to remain in hospital for approximately one week.
His public engagements have been cancelled until October 20.
Before the operation, Leo had told worshippers during his Sunday Angelus address that doctors had discovered a small nodule during routine medical examinations.
He said the abnormality had been detected early and appeared localised.
He thanked Catholics for their prayers and explained that he had accepted medical advice to undergo surgery.
Brothers Spoke Before Their Treatments
Deborah Prevost said the two brothers had spoken shortly before Louis began his latest cancer treatment.
During their conversation, the Pope informed his family about his approaching lung operation.
“He called to let us know what would be happening,” she told CBS News.
She said she remained hopeful about both men’s recoveries but did not have detailed information about the Pope’s medical condition.
Louis later told Newsmax that he had received word shortly after his brother’s operation that the pontiff was awake and recovering comfortably.
The brothers grew up in the Chicago area alongside another older brother, John Prevost.
Leo, whose birth name is Robert Francis Prevost, became the first American-born Pope when he was elected in May 2025.
Louis previously spoke publicly about his younger brother’s religious interests during childhood.
In an interview following the papal election, he recalled that Robert had shown an interest in becoming a priest from an early age.
The brothers have remained in contact since Leo assumed leadership of the Roman Catholic Church.
