Why did Joe Biden not know he was a prostate cancer risk?

There are all kinds of questions being raised in Washington about Joe Biden's latest medical shock. Principally, how come the former president of the United States was not checked for prosrate cancer every year as part of his annual medical check-up? In 2014 he was given a PSA test, the normal blood check to see if there are any signs of prostate problems, but no PSA test since then. This goes against all that is known about checking for this disease. For all men, president or not, as soon as there is the slightest signal that the prostate is not behaving the way it should, then doctors advise two ways forward: to have a biopsy to detect any sign of cancer or to watch and wait which means having checks every year to see if the PSA level has increased to an unacceptable figure. None of this appeared to have happened with Biden. We don't know what the 2014 PSA level was but eleven years later he is suddenly diagnosed with an aggressive cancewr in the prostate and also in his bones. This is quite shocking and makes no sense. In the lead-up to this diagnosis there must have been clear signs that Biden's prostate was malfunctioning. There would have been a build-up over a period of years and if annual PSA tests had been carried out it would have been detected. A full explanation is needed.