Focus - Health Tips » Is the PSA Test Worthless?
Is the PSA Test Worthless?
By Dr. Moghissi - October 2004
Most of my male patients (or at least most of them over 35) are worried about prostate cancer. Although they are reluctant (or at least unhappy) to have a rectal exam, they are usually interested in having the blood test for PSA. As a screening test, the PSA has always been controversial. In recent years the recommendation has been to draw a PSA on all men over 50 annually. But a new study in this month’s issue of Journal of Urology puts this into question.
First, some basic information. Prostate Specific Antigen (PSA) in the blood only comes from the prostate, but is not specific for prostate cancer. Any irritation or enlargement of the prostate can cause elevation of the PSA. Some of the highest PSA levels I’ve ever seen have been due to prostatitis, or an infection of the prostate. Benign prostatic hypertrophy (BPH) causes an elevation in PSA and is very common in men over 40 (this is why older men get up multiple times at night to pee).
20 years ago a study showed that the relationship between elevated PSA and prostate cancer was about 50%. The same authors continued to gather data, and found that today relationship is only 2%. In the past 5 years, they found that the PSA is more closely related to benign (non cancerous) enlargement. They don’t really know why this has changed, but it may have to do with the fact that we are now checking lots of healthy men, whereas before they may have only been checking men where there was a suspicion of cancer.
An annual rectal exam is still pretty specific; an abnormal exam (finding a hard nodule) has a greater than 90% chance of being prostate cancer. Unfortunately, this is the least favorite part of the physical, for the patient and me!
It is important to note that PSA is still useful for following patients with prostate cancer. If the PSA starts going up after treatment for prostate cancer, there is a high chance of recurrence of the cancer.
Another complicating factor is that pretty much all men will get prostate cancer if they live long enough, but very few will die of it. The death rate from prostate cancer is 226 per 100,000 men over age 65 (the remaining 99,774 will die of other causes). If you biopsy the prostates of men in their 70’s, 70% will have prostate cancer. Obviously only very few of those 70% need to be treated. Unfortunately, we don’t necessarily know who should and shouldn’t be treated. This obviously is an area of active research.
I’m sorry if I’ve totally confused you on this one, but I wanted to impress upon you how controversial this all is. Hopefully we’ll get better answers in the not too distant future.
Copyright 2017 Jasmine Moghissi, MD,PC.