It's the only way to be sure -- read the disclaimers in the small print, optional.
Tests! And of course, get insurance and government to pay for them. And pay, And pay/ And pay.
A good analogy for this is auto accessories. They develop and market them and suddenly everyone needs the item. Of course it may end up killing you do to power, speed, loss of control.
Person psa experience: did blood test, doc said psa was elevated, could be a false reading, could mean I had sex the morning of the blood test(very likely).
Second blood test: all good, normal numbers.
The new doc explains prostate cancer this way, most men will die WITH prostate cancer, not from prostate cancer.
And your age correlates with the percentage of.
That was stated in this article: 40-49=-9 40% chance, etc.