Doctors have detected cancer in Britain's King Charles III, Buckingham Palace said in a statement Monday. The unspecified cancer was discovered as doctors treated the monarch for an enlarged prostate just over a week ago.

British Prime Minister Rishi Sunak told CBS News partner network BBC News Tuesday that Charles' cancer was "caught early."

Sunak said, "Like everyone else, we're shocked and sad, and just all our thoughts are with him and his family. Thankfully, this has been caught early and now everyone will be wishing him, that he gets the treatment that he needs and makes a full recovery. That's what we're all hoping and praying for."

What type of cancer does King Charles III have?

It is understood that the king has been diagnosed with cancer elsewhere in his body, not of the prostate.

The king, 75, was discharged one week ago following treatment for an enlarged prostate, which the palace said was not cancerous. During that treatment, however, a "separate issue of concern was noted. Subsequent diagnostic tests have identified a form of cancer."

Buckingham Palace said Charles had "commenced a schedule of regular treatments," and that during that treatment he would "postpone public-facing duties." It said he would continue with his official business and office work as usual.

"The King is grateful to his medical team for their swift intervention, which was made possible thanks to his recent hospital procedure. He remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible," the statement said, adding that the monarch had "chosen to share his diagnosis to prevent speculation and in the hope it may assist public understanding for all those around the world who are affected by cancer."

How long has Charles been king?

Charles has been king for less than a year and a half after inheriting the monarchy upon the death of his mother, Queen Elizabeth II, in September 2022. He was crowned several months later, on May 6, 2023. His health was generally understood to have been good. He had a noncancerous growth removed from his face in 2008, according to The Associated Press.

Charles was admitted a couple weeks ago for the prostate treatment to the same private London clinic where his daughter-in-law, Kate, the Princess of Wales, underwent an unspecified abdominal surgery. She was also back at home in Windsor and was said to be recovering well as of Jan. 29.  

Kate's husband, William, the Prince of Wales, who is next in line to inherit the throne after his father, is expected to return to his royal duties this week after taking some time off to support his wife following her surgery, according to Kensington Palace, William and Kate's official residence.

BBC News reported the king personally informed his immediate family, including William, of the diagnosis. Sources confirmed to CBS News on Monday that the king's younger son, Prince Harry, had spoken with his father about his diagnosis, and on Tuesday he arrived back to the U.K. to visit the monarch.

Harry, the Duke of Sussex, moved to the U.S. several years ago with his wife Meghan as they relinquished their roles as senior working members of the royal family.

Sunak said in a social media post on Monday that he was "wishing His Majesty a full and speedy recovery," and that he had no doubt Charles would "be back to full strength in no time."

President Biden reacted to the news during a campaign trip in Las Vegas, ahead of Nevada's upcoming presidential primary, telling reporters he had just been informed of the British monarch's diagnosis, was "concerned about him," and would "be talking to him, God willing."  

Later on social media, Mr. Biden, whose oldest son Beau Biden died of brain cancer in 2015, said he and first lady Jill Biden were praying for the king's recovery.

"Navigating a cancer diagnosis, treatment, and survivorship takes hope and absolute courage," the president said. "Jill and I join the people of the United Kingdom in praying that His Majesty experiences a swift and full recovery."

Alex Sundby contributed reporting.

In:
• King Charles III
• British Royal Family
• Prostate Cancer
• King Charles
• Cancer

Tucker Reals

Tucker Reals is cbsnews.com's foreign editor, based in the CBS News London bureau. He has worked for CBS News since 2006, prior to which he worked for The Associated Press in Washington D.C. and London.