That's the gold standard that hard-nosed researchers are looking for. Until results are in, there are what are called intermediate markers. These are objective scientific measures of real progress, and they're quite valuable. One reason is that there is a great sense of reward when you can see real results. You know you're moving in the right direction.
Markers tell researchers that they are changing what they want to change.
Since prostate cancer can take decades to develop, it could be many years before you know if you've succeeded in protecting yourself against the disease. The same is true with other diseases. Take heart disease as an example. Doctors and patients rely on intermediate markers, the most well known of which is the cholesterol test. Patients take great satisfaction in lowering their cholesterol levels, although it does not guarantee that they will avoid a heart attack.