The news of Joe Biden's prostate cancer diagnosis has raised questions about why the disease wasn't detected earlier.

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.

Biden’s diagnosis comes at a difficult time for the former president, as scrutiny grows over his decision to run for a second term last year.

Speaking to the BBC 's Americast podcast, Tapper gave some examples of where Biden's decline was clear and how it was hidden from the public. Biden's time in office was plagued with rumors about his health,

Jake Tapper and Alex Thompson's book has already generated a national debate about whether the White House deceived the public about the president's cognitive state and how Biden's late exit from the race undermined the Democratic Party's chances of stopping Trump.