Prostate cancer is the most common cancer in American men after skin cancer — per the American Cancer Society (ACS), it impacts about 1 in 7 men. However, this form of cancer tends to be easily treatable, particularly with early detection. As a screening tool, the prostate-specific antigen (PSA) test can produce cancer diagnoses earlier so that treatment might be more successful.
What Is a PSA Test?
A prostate-specific antigen test detects the level of prostate-specific antigen (PSA) in a man's blood. According to the National Cancer Institute (NCI), PSA is a protein that both normal and malignant cells of the prostate gland can produce.
To perform this test, your doctor will take a blood sample — during an annual wellness exam or another appointment — and send it to a laboratory for analysis. The laboratory will generally return results as PSA per milliliter (ng/mL) of blood.
Why Are PSA Tests Important?
In men, a high PSA level can be an indicator of prostate cancer. The U.S. Food and Drug Administration (FDA) originally approved the test to monitor patients with an existing prostate cancer diagnosis. But the governing body later expanded that approval so the test could be used as a prostate cancer screening tool, in conjunction with a rectal exam, for undiagnosed or asymptomatic patients.
Do I Need to Have a PSA Test Done?
Because the prostate is an exclusive part of the male anatomy, this precludes women from needing PSA tests. However, women have their own anatomically specific set of preventive care screenings, such as pap smears and mammograms.
The ACS recommends that men discuss prostate cancer screening with their doctor at different ages, depending on their risk level for prostate cancer. The lower your risk, the longer you can wait before needing to ask about this antigen test.
- Average risk = Age 50: The ACS also clarifies that the patient should be expected to live at least 10 more years because prostate cancer grows slowly. This makes detection less beneficial for patients with an already shorter life expectancy.
- High risk = Age 45: High-risk patients include African Americans and men whose first-degree relative (father, brother, or son) received a prostate cancer diagnosis before age 65, which is considered an early age.
- Higher risk = Age 40: Patients are at higher risk for prostate cancer if they have more than one first-degree relative who was diagnosed with prostate cancer at an early age.
The Risks and Limitations of PSA Tests
The ACS also clarifies that men should only decide whether to get screened after they have received complete information concerning the potential uncertainties, risks, and benefits of screening for prostate cancer.
This is because early detection does not always reduce the risk of dying from prostate cancer. Prostate cancer cells can grow too quickly and spread to other parts of the body prior to detection. Conversely, prostate cancer cells can grow so slowly that they don't warrant the need for more invasive cancer treatments such as surgery or radiation. Doctors refer to the latter as "overdiagnosis" of non-life-threatening tumors and "overtreatment" of those tumors, per the NCI.
PSA tests can also produce false-positive or false-negative results, both of which can be problematic.
- False-positive result: Indicates a high PSA level even when no cancer cells are present. This can cause a man and his loved ones needless stress and anguish or require additional — and ultimately unnecessary — tests, which could be more invasive and potentially harmful.
- False-negative result: Indicates a low PSA level even though the man does have prostate cancer. This means the cancer could continue to grow and spread undetected and, therefore, untreated.
What Happens After a PSA Test?
If the results of a PSA test do not yield a prostate cancer diagnosis, your doctor will plan out the timing for future screenings based on your current results, per the ACS.
- Less than 2.5 ng/mL: May only need to be retested every two years
- More than 2.5 ng/mL: Requires annual re-screenings
Should the PSA test results suggest possible prostate cancer, your doctor will order other tests, such as a transrectal ultrasound and prostate biopsy, to confirm the diagnosis. If you do have prostate cancer, your doctor will then begin discussing your treatment options going forward.
Like other vital preventive care measures and screenings, the prostate-specific antigen test can save lives through early detection of prostate cancer. If you or your loved one is at risk for prostate cancer and approaching the ages outlined by the ACS, speak with your doctor about the PSA test and other factors related to prostate health.