Former US President Joe Biden had not received a test for prostate cancer, known as a PSA, for more than a decade before he was diagnosed with an advanced form of the disease last week, a spokesperson said on Tuesday.

The latest comments from the former Democratic president’s camp come amid questions from Republicans and some health professionals about why his cancer was not caught before reaching an advanced stage.

Biden, 82, has also faced broader questions about whether he and his allies withheld critical information from the American public about his ability to serve in the White House. A new book, “Original Sin,” details widespread concerns about Biden’s mental acuity amongst aides as he pursued reelection last year.

“President Biden’s last known PSA was in 2014,” the Biden spokesperson said on Tuesday. “Prior to Friday, President Biden had never been diagnosed with prostate cancer.”

A PSA test, or prostate-specific antigen test, is a blood test that is used to screen for prostate cancer.

Some health professionals consulted by Reuters expressed surprise at the diagnosis given that most prostate cancers are detected at an earlier stage and that presidents undergo thorough health monitoring.

Still, others said it is not unusual to discontinue testing for prostate cancer in older patients because the test is less reliable in that age group. Prostate cancer has a much higher survival rate than most other cancers.

In 2012, the US Preventive Services Task Force recommended against PSA-based screening for prostate cancer in men of all ages. The task force reversed the recommendation in 2017, advising against screening for men older than 70.

Biden, who ultimately abandoned his reelection bid and left office in January, was in his early 70s at the time of his 2014 screening.

“It is very reasonable to discontinue PSA screening at age 72, regardless of health status, or significantly decrease the frequency of screening,” said Dr. Scott Eggener, a urologic cancer specialist and professor of surgery at the University of Chicago.

Biden’s office said he had been diagnosed on Friday with “aggressive” prostate cancer that had spread to his bones. Cancers that have spread, or metastasised, are considered stage 4, the most advanced.

US President Donald Trump and Vice President JD Vance are amongst the Republicans who have offered well-wishes to Biden while also raising questions about the timing and nature of his cancer diagnosis.

Trump received a PSA test as part of his latest annual physical exam, according to results released in April.