After Biden's cancer diagnosis, the nation is puzzled: How could something like this have been overlooked in the most closely watched man in the country?

When it comes to their own health, American presidents have never been entirely trustworthy. Woodrow Wilson, for example, was barely able to function in his final years as president in 1920 and 1921 after suffering several strokes; his wife secretly handled his duties. Dwight Eisenhower's personal physician covered up the president's heart attack in the 1950s, claiming he was merely suffering from indigestion. Ronald Reagan, for his part, desperately tried to conceal the early symptoms of dementia toward the end of his term.

Her successor, Joe Biden, is accused of something similar. There are already books addressing the question: Shouldn't his limited mental capacity have been noticed before the election campaign with Donald Trump?

Now a second suspicion has emerged. The American public is asking itself how it is possible that prostate cancer in one of the most medically monitored people in the world is only discovered at such an advanced stage? Biden was found to have a tumor that has already spread to his bones. Experts can't promise him a life expectancy of more than three to five years.

The question: "How could this happen?" arises precisely because there is a corresponding early detection test: the PSA test, which determines the blood level of the so-called prostate-specific antigen. Experts recommend this test for every man over the age of 45. However, men over the age of 75 (more precisely, with a life expectancy of less than ten years) are advised against it. "So, from a medical perspective, the president's doctor did nothing wrong by not determining this level in Joe Biden," says Christian Gratzke, head of urology at Freiburg University Hospital.

The former president's last health checkup was posted online in February 2024. Eleven doctors from various disciplines examined Biden thoroughly, but apparently omitted his prostate. Neither the name of a urologist nor a PSA level can be found on the examination report.

The fact that experts no longer recommend PSA testing in old age is, paradoxically, due to the fact that the probability of finding something is too high. Roughly one in two seniors at this age has a tumor in their prostate. However, because these tumors generally grow very slowly, they won't be dangerous for most. "We don't want to detect these cancers at all to spare those affected the side effects of treatment," says Gratzke.

But even in younger people, the test is often inaccurate: Of 1,000 symptom-free men with a suspicious PSA level (≥ 4 nanograms per milliliter), only 330 actually have prostate cancer. In 670 cases, the positive test is a false alarm because, for example, the patients only have an enlarged or inflamed organ. The PSA test certainly has its weaknesses, admits Beat Roth, chief physician of urology at Bern's Inselspital, "but we simply don't have anything better."

Doctors are therefore trying to cope with this deficiency as much as possible. A steep increase compared to a previous value is considered particularly suspicious of a tumor. This means that something must have changed significantly in the organ. This is why patients with a slightly elevated PSA are now called in for a follow-up examination every four years . With a moderate increase, the follow-up examination is even every two years. With a significantly elevated value, an annual follow-up examination was previously required. This will soon change with a new guideline . In the future, magnetic resonance imaging will be used to search more thoroughly for tumors in such cases, and samples will be taken from suspicious areas.

There are other reasons why 10 to 15 percent of prostate cancers are missed by the PSA test. One of these is "rocket tumors," which grow within months and become dangerous to those affected. Another is carcinomas that do not produce PSA. The reason: As they degenerate, they lose this characteristic of other prostate cells. They, too, cannot be detected by the test. One or the other applies to approximately one in 50 tumors. Almost 10 percent of cancerous tumors are only discovered when they have already metastasized throughout the body – either because they are missed or because the men have opted not to have a PSA test.

It's entirely possible that Biden's tumor would not have been detected despite a PSA test. In the former president's case, the cancer was revealed by late symptoms such as blood in the urine, difficulty urinating, or localized pain. "But I'm still certain it would have helped Biden if he had been examined earlier," says Roth. Because before these symptoms appear, locally enlarged cancers can be felt by a doctor with a finger.

One might also ask: Shouldn't a PSA test be mandatory for a president who wants to prove his fitness for office at over 80? A head of state who receives a cancer diagnosis while in office isn't necessarily in the country's best interests.

Donald Trump, 78, did things differently; he went on the offensive during his first candidacy. Back then, he even boasted about his excellent PSA level. Even at his last official physical a few weeks ago, his prostate health results were more than satisfactory. The same applies to the condition of his heart and blood vessels. The latter can either be attributed to the health-promoting effects of golf or, given the lifestyle of the self-proclaimed fast-food fan, with a body mass index of 28, is quite astonishing.