King Charles has cancer. Here's what you need to know.

On Monday evening, Buckingham Palace suddenly announced that King Charles III had been diagnosed with cancer, less than 18 months into his reign. He is being treated as an outpatient in London.

The British monarch's diagnosis prompted an outpouring of sympathy from leaders around the world, with President Biden saying he was praying for “a quick and complete recovery,' and British Prime Minister Rishi Sunak, who described himself as 'shocked and saddened' by the news. “He will simply be in our thoughts and our prayers,” Mr Sunak said told BBC radio on Tuesday. “Many families across the country listening to this will be affected by the same thing.”

Here's what you need to know about the king's condition and its implications for the British monarchy.

What do we know about the king's diagnosis?

Not very. Buckingham Palace said on Monday evening that “a form of cancer” had been diagnosed, but did not say what type, and asked reporters not to attempt to contact those involved in Charles' care.

The palace said doctors identified “an area of ​​concern” when they treated Charles, 75, for an enlarged prostate last month. They confirmed cancer – but not prostate cancer – with subsequent testing.

Charles, the statement added, began a schedule of regular treatments on Monday and “remains entirely positive about his treatment and looks forward to returning to full public service duties as soon as possible.”

That the palace has not publicly identified the cancer is no surprise; the British royal family tends to be very private about health matters. Three weeks ago, when Charles' planned prostate treatment was made public, the announcement was seen as a break from tradition.

The palace said the king, who as Prince of Wales supported several cancer charities, had chosen to share his diagnosis “to avoid speculation and in the hope that it would increase public understanding for everyone around the world affected by cancer.” is affected.”

What are the king's normal duties, and who will perform them now?

On the advice of his doctors, Charles will temporarily refrain from public appearances, which typically include speeches, visits to charities he supports, community projects and foreign travel.

But the king will continue to carry out his duties as Britain's largely ceremonial head of state. This includes a weekly meeting with Mr Sunak and a day-to-day approach “red box” with official paperworksuch as signing routine government documents and receiving the credentials of new ambassadors to Britain.

Queen Camilla will carry out a full schedule of official engagements while her husband is treated, the palace said, and Prince William, the heir to the throne, will return to public engagements this week. William, 41, had put his public duties on hold for a few weeks as his wife, Catherine, was admitted to hospital for abdominal surgery in January. She is now recovering at home.

Officials said there were no plans to appoint state advisers to act in King Charles' place – a procedure that could indicate the sovereign was unable to fulfill his duties due to illness.

What happens if Charles can no longer perform his duties?

If the king is temporarily unable to act as head of state due to illness or travel abroad, state advisors have been appointed to fulfill his duties.

Some basic constitutional actions still require the king to help formalize them, including the dissolution of parliament to make way for new elections; appointing new members to the House of Lords, the unelected upper chamber of Parliament; and appointing a prime minister.

If Charles became incapacitated, he could remain king, but with a 'regent' who would fully assume the duties of the sovereign. The regent would be next in the line of succession: Prince William.

below the 1937 law that regulates the procedure, the king himself would not make the decision. Instead, a group including Queen Camilla and some of Britain's most senior state officials, including the head of the English judiciary and the Speaker of the House of Commons, would sign a declaration of incapacity for worksupported by medical evidence.

William would then take a series of formal oaths, including the oath that he would 'be faithful and bear true allegiance to King Charles III, his heirs and successors in law', before beginning his new duties.

If the king were to recover later, the regency could be terminated by a declaration of 'removal of incapacity'.