WHAT IF I HAVE AN ELEVATED PSA
So what do you do when you have a high PSA? Is simply doing a scan enough? The scan not only helps men know if there is an area of aggressive prostate cancer, it also gives you information about how big the prostate gland is. PSA mostly comes from the prostate gland, not from prostate cancer. That of course confuses things that PSA can come from both cancer and the benign prostate gland. When cancers are small, most of the PSA is coming from the prostate gland, not from the prostate cancer, itself. This ratio of prostate gland size to PSA is called PSA density. For example, the ratio of a 50 cc prostate to PSA should be about 10 to 1. So a man who has a 50 cc prostate, should have a PSA of around 5 or so. That would be considered normal for that individual. If a person had a large prostate, 100 cc prostate, a normal PSA could be around 10. So we have to stop interpreting PSA like one size fits all — the threshold of a PSA 2.5 or 4 number as if this is the last word on what’s an abnormality or not. Until you find out how big the prostate gland is, then you really can’t interpret the PSA and you can’t give reasonable information about the risk of underlying prostate cancer. The bottom line is when we do imaging, we not only get information about the presence or absence of cancer, but we also help put the PSA in context. PSA has been a very useful test, but its over interpretation and forgetting how much variation there is in men’s prostate glands that can become a real problem.
DEFINITION OF PSA DENSITY
As men get older, almost all develop enlargement of the prostate gland. Invariably, PSA rises as a result. When checking PSA the question should not be, “Is it above 2.5 or 4.0?” The question should be, “Is the PSA excessive considering the size of my prostate?” Prostate size can be measured with ultrasound or MRI. A normal PSA is one point for each 10 cc of prostate volume. Abnormal is greater than 1.5 points per 10 cc.