WASHINGTON  -  Joe Biden’s announcement that he has been diagnosed with prostate cancer has revived questions about what health issues the former US president was dealing with while he was in the White House. In a statement on Sunday, Biden’s office said the 82 year old had received the diagnosis on Friday after seeing a doctor for urinary symptoms. Some doctors have expressed surprise that the aggressive form of cancer, which has spread to his bones, had not been detected earlier.

Others pointed out that cancers can grow fast without the patient displaying symptoms - and that men over 70 are not routinely screened.

President Donald Trump told reporters on Monday his predecessor should have been more transparent with the public, seeming to suggest - without offering evidence - that the cancer diagnosis had been covered up. “I think it is very sad actually. I am surprised that the public wasn’t notified a long time ago,” Trump said at an event at the White House. “It could take years to get to this level of danger. So, look, it’s a very, very sad situation. I feel very badly about it, and I think people should try and find out what happened.”

Biden has yet to respond to Trump’s comments, which came amid reports that the Democrat’s aides sought to conceal other deteriorating health conditions from the public ahead of the 2024 election.

Republicans claim that Biden, who ran for re-election as the oldest president in history at 81, was mentally and physically unfit for office. He dropped out of the race last summer after a disastrous debate performance against Trump.

According to Original Sin, a new book by journalists Jake Tapper and Alex Thompson, Biden was unable to recognise Hollywood actor and Democratic donor George Clooney or to recall the names of key aides in his final year in office.

The authors write: “Biden’s physical deterioration - most apparent in his halting walk - had become so severe that there were internal discussions about putting the president in a wheelchair, but they couldn’t do so until after the election.”

The publicity generated by the book has forced senior Democrats to field questions on why they did not do more to respond to Americans’ concerns about Biden’s health as he campaigned for re-election.

“It was a mistake for Democrats to not listen to the voters earlier,” Senator Chris Murphy said on Sunday.

After the news of Biden’s diagnosis, Vice-President JD Vance wished him well but then asked whether Biden’s doctors or staff members sought to keep the public from knowing about the true state of his health.

“This is not child’s play, and we can pray for good health, but also recognise that if you’re not in good enough health to do the job, you shouldn’t be doing the job,” he added.

Dr Ezekiel Emanuel, an oncologist who worked as a Covid adviser to the Biden White House, was among those claiming that Biden probably had been ill with cancer for some time, without necessarily knowing it.