Until last summer, I didn't even know what PSA stood for or why I needed it. When the results started climbing, however, I quickly found out.
PSA stands for Prostate-Specific Antigen, which is a protein produced by cells in the prostate gland. It's always in the blood in men in very low levels. An elevated level of PSA can indicate prostate cancer, prostate infection or irritation, such as that from a digital rectal exam.
Generally, a PSA test of 4 or below has been considered normal. I had a string of three annual PSA tests that were all under 4.0. But my general practitioner noticed a troubling trend last spring -- the results continued to climb.
My first test in 2003 was 2.7; in 2004 it was 2.77; in 2006 it was 3.81; and in 2007 it climbed to 4.29.
My doc never detected anything in the digital rectal exams, the common way of checking for prostate cancer until the PSA tests came along in the late 1980s. Although the 4.29 was considered only slightly outside the normal range, I went in for a follow up PSA.
A follow-up PSA was still in the same range, and I was referred to a urologist at University of Washington hospital.
Because there are other factors that can influence PSA, I was told to abstain from sex for a week and stop bicycling for two weeks. Both of these activities have been found, at times, to slightly elevate PSA.
My third PSA test of 2007 dropped slightly, to 4.02. That wasn't far enough for my doctors though, and they scheduled a biopsy for me. I'll write more about that later.
What is normal
Researchers are still wrestling over what PSA level should trigger a biopsy. The 4.0 nanograms per milliliter (ng/mL) level in general has dropped. The National Cancer Institute published the following ranges:
- 0 to 2.5 ng/mL - low
- 2.6 to 10 ng/mL is slightly to moderately elevated
- 10 to 19.9 ng/mL is moderately elevated
- 20 ng/mL or more is significantly elevated
The point I want to make here is the importance of the PSA test in detecting prostate cancer.
As with any test, it is not foolproof. Occasionally it gives a false positive, sometimes a false negative. There's a debate over whether the 4.0 level for action should be lowered.
For me, and for many men I talk to at my cancer support group, it wasn't so much a one-time PSA test that triggered action. It was velocity, and rate at which the PSA increased. An increase from 2.7 to 4.29 might not sound that radical, but consider that rate of growth was nearly 60% over four years.
Based on my experience, and that of many other men, I'd recommend an annual PSA test. That gives doctors a baseline to check any changes in PSA over subsequent tests. If you are over 50, and your doctor is still relying on just a digital rectal exam to check for prostate cancer, I'd suggest you ask him to include the PSA as well.
More reading at National Cancer Institute: PSA Q&A; WebMd: Prostate-Specific Antigen