Overview: As men age, most will begin getting tested for level of prostate-specific antigen, or PSA. A high level can indicate an issue with the prostate, including prostate cancer. Men should know how the test is given and how often, what the difference between PSA and free PSA is, what happens if a test comes back with high numbers, and why doctors may not recommend a PSA test at all.
What Is Prostate-Specific Antigen (PSA)?
PSA is an enzyme produced by the prostate. It helps liquefy semen so sperm can swim freely and may also make it easier for women to become pregnant by dissolving cervical mucus. The prostate is constantly producing PSA, so a low level of it is found in every man’s blood serum.
Around age 25, your prostate will start slowly growing and producing more PSA. As a result, as men age, they can expect higher PSA levels. Doctors generally view 4 nanograms per milliliter (ng/mL)or less as normal.
How is PSA Tested?
PSA is checked with a blood test. Since it’s fairly easy and noninvasive to do, some men opt to have a PSA test performed as part of their regular checkups as they age. Generally, a doctor will ask if you want to perform the test, for reasons we’ll get to.
Why Does My Doctor Test For PSA?
PSA is an early clue that there may be an issue with the prostate. It’s not a silver bullet for determining possible cancers, so often a PSA test is paired with the digital rectal exam (DRE) to check for lumps, hardness, signs of enlargement, or inflammation. Depending on the results, a doctor may recommend another test for “free PSA.”
What’s the Difference Between PSA and Free PSA?
PSA comes in two forms, “bound,” which means it’s tied to other enzymes, or “free” which means it’s just floating through the blood. Over time, doctors have found that men with an elevated PSA level who have a high level of free PSA, more than 25% of an elevated total, are more likely to have a benign medical condition, like an enlarged prostate. Men with a low level of free PSA are more likely to have prostate cancer.
How Accurate Is The PSA Test?
The question of accuracy is the crux of the issue some doctors have with the PSA test, because the short answer is, not very. On its own, the test has an elevated rate of both false positives and false negatives, for a few reasons:
- Benign conditions, like an enlarged prostate, or non-cancerous conditions like prostatitis, can elevate PSA.
- Medications to treat urinary problems or large doses of certain types of chemotherapy may artificially lower PSA.
- Obesity can also lower PSA.
False positives can be unpleasant because they mean more testing with the associated time and costs, sometimes even including a prostate biopsy. False negatives can mean men with prostate cancer think nothing is wrong and delay treatment.
This is generally why even doctors who advocate for the PSA test pair it with other tests and don’t treat it as the be-all and end-all of cancer diagnosis.
And even if you do have prostate cancer, there may not be a point in testing for it anyway. In fact, your doctor might even tell you not to.
Why Might My Doctor Recommend Against a PSA Test?
Currently one of the broader discussions of medical ethics involves overdiagnosis. Thanks to decades of advances in screening, testing, and visualization, we’re able to spot all sorts of conditions and problems that would otherwise not have been found by doctors.
The question, though, is whether it matters. “Overdiagnosis” means a problem that would have no impact on your overall health and well-being is found and potentially treated when there’s no benefit to the patient.
In the case of prostate cancer:
- Even when cancer spreads to the lymph nodes or nearby areas, the survival rate over five years is nearly 100%.
- The average age of a man diagnosed with prostate cancer is 66, and the average life span of a man is 77 years.
- There are 3.1 million American men who’ve been diagnosed with prostate cancer at some point who are still alive right now. That’s nearly 1% of the entire population of America.
- A survey of autopsy results found that up to 70% of men over 65 in the sample had some form of undiagnosed, or “silent,” prostate cancer. This doesn’t mean 70% of men have prostate cancer and don’t know it, just that it goes undiagnosed in a large number of people because it doesn’t impact their health.
In other words, the average man diagnosed with prostate cancer has other medical problems to deal with that are more urgent and may be far more likely to be fatal.
According to CDC mortality data, while roughly 28% of American men over 65 will die due to some form of cancer, 25% will die due to heart disease. At age 85, heart disease becomes the number one cause of death in men, while all cancers drop to 15%.
Since this prostate cancer is unlikely to be an issue, doctors may view it as unethical to treat it beyond a certain point, as it will impact the patient’s quality of life for no real benefit. Even a biopsy, where doctors take a sample of your prostate to test, can be a painful surgery with a long recovery.
Should I Get A PSA Test?
The answer to that question is, it’s up to you and your doctor. If you’re concerned or just want to cover the bases, it’s a simple test.
However, before you schedule the PSA test, have a conversation with your doctor about your risk of prostate cancer. If cancer doesn’t run in your family and you’re sticking to a doctor-supervised healthy lifestyle, there may not be a good reason to start screening yet.
If you are concerned, consider a digital rectal exam (DRE) instead. While people may joke about it, finding lumps or hardness is a more reliable sign than a PSA. A DRE is quick and painless, and if you’re really concerned about prostate cancer, a little embarrassment is a small price to pay.
For More Information
To learn more about the prostate, what it does, and how to care for it, see our Users Guide to the Prostate. For more information about erectile dysfunction after prostate surgery, check out this blog post.
If you struggle with erectile dysfunction, eDrugstore has your back. Browse our medication guide, or call 1-800-467-5146 to schedule a free, confidential consultation with one of our U.S.-licensed physicians. Virtual health visits and shipping are always free.
Dan is a long-time freelance writer focusing on technology, science, health, and medicine, with a lifelong interest in physics, biology, and medicine. His work has taken a particular focus on scientific studies “beyond the headlines,” reading the study to more closely examine the results.