The wife of Pope Leo XIV’s brother says her husband is also receiving treatment for cancer after the Vatican announced the Pope has the disease.

Deborah Prevost, the wife of the Pope’s eldest brother, Louis Prevost, told CBS News, the BBC’s US partner, on Tuesday that her husband has a form of blood cancer. It is unclear how advanced it is.

Her comments came on the same day that Pope Leo, 71 – the first US-born head of the Catholic Church – underwent what the Vatican described as “successful” surgery for lung cancer. He is expected to remain in hospital for a week.

Deborah Prevost said the family was “going through a lot” and that they are “keeping spirits up for both of them”.

She said her husband was being treated for multiple myeloma as part of a clinical trial at a hospital in Florida where they live. He was first diagnosed with cancer in 2017 and had undergone treatment in 2019, but “fell out of remission” three months ago.

Multiple myeloma affects the blood, bone marrow, and can impact kidneys, according to a factsheet by the UK’s National Health Service (NHS).

It is not currently considered curable but the Multiple Myeloma Research Foundation says on its website that survival rates have significantly improved in the past decade.

Louis Prevost confirmed his cancer diagnosis in a separate interview with US news outlet Newsmax, saying he was undergoing CAR-T cell therapy.

This involves reprogramming a patient’s immune cells to recognise and destroy blood cancers, the NHS states.

Louis Prevost told Newsmax’s Finnerty programme that it had been a shock to learn his brother also had cancer.

“I got a message from his right hand that he was out of surgery, awake, feeling good, and was in no pain,” he said of the Pope’s condition.

“So, we were all in high hopes and high spirits hoping for the best.”

Deborah Prevost said the brothers spoke last week as her husband prepared to go to hospital.

“He called to let us know what would be happening,” she said. The Pope announced on Sunday he would be operated on “in the coming days” after a nodule was found on his lung during a medical check-up.

“We keep praying, keeping spirits up for both of them,” said Deborah Prevost.

The Pope underwent a 90-minute surgery on Tuesday at Rome’s Gemelli Hospital and was subsequently diagnosed with lung adenocarcinoma – a type of cancer usually found in the outer part of the organ. During the surgery, a lower lobe of his right lung was removed, the church said in a medical bulletin.

“The operation was successful and there were no complications,” the Vatican said. “After the operation, the Pope awoke normally and returned after a brief period of observation to his room.”

The pontiff had a “peaceful night” in the hospital, the Vatican said on Wednesday morning.

Adenocarcinomas develop in cells that produce mucus and are one of the most common types of lung cancer.

The long-term prognosis depends on a number of things, including the stage of the cancer when identified and the person’s overall health. The earlier it is spotted, the better, and treatments have improved over the last few decades.

Some adenocarcinomas are picked up early – before symptoms develop – during routine tests. At later stages, lung cancer can cause a persistent cough, breathlessness, fatigue and weight loss.