Heraldo de Madrid - How Biden cancer diagnosis could have gone undetected

The 82-year-old received the diagnosis last week after he experienced urinary issues and a prostate nodule was found, his office said Sunday.

While President Donald Trump said he was "saddened" to learn of his rival's condition, a chorus of Republicans led by Vice President JD Vance and Donald Trump Jr said or shared conspiratorial posts to the effect that Biden and his White House medical team had long concealed his illness for political purposes.

Questions over Biden's health dogged him throughout the waning months of his presidency and his short-lived reelection campaign. And they have been renewed in recent weeks ahead of the expected release of a book detailing what it calls his declining physical condition.

Prostate cancer, the most common among men, is typically diagnosed much sooner than other kinds of cancer. It can be caught in its early stages using blood tests that measure for a protein called PSA.

Medical experts interviewed by AFP said the late identification of an advanced cancer would not be unheard of, even for a former president receiving top-of-the-line medical care.

"We can't rule out the possibility that it was an aggressive form that developed quickly," said Natacha Naoun, an oncologist with France's Gustave-Roussy Institute.

Annual PSA screening after the age of 70 is not universally recommended.

The US Preventive Services Task Force advises against it, reasoning that the risk of false positives and the harms from biopsies and treatment outweigh the benefits.

"It could be they decided to stop checking PSA annually, and then he had urinary symptoms," said Russell Pachynski, an oncologist with Washington University in St. Louis, Missouri, who told AFP that prostate cancer patients do not always experience telltale pains or signs.

It is also possible that Biden was undergoing routine screenings, but that those checks failed to turn up indications of cancer, Pachynski said.

"Maybe it was just unlucky that his particular cancer didn't express a lot of PSA and he still had a normal PSA. In that setting, you would not go checking the prostate or do a biopsy, etcetera, unless it was driven by symptoms."

Otis Brawley, an oncologist and epidemiologist at Johns Hopkins University, said studies have shown both PSA testing and rectal exams are imperfect.

"It is not unusual for a man to be diagnosed with metastatic prostate disease despite normal annual screening," he told AFP. "This is part of the limitations of prostate screening."

D.Ferrer--HdM