Prostate Specific Antigen

When you go to your doctor for a yearly visit, you may be offered a blood test to search for prostate cancer. This blood test is called a Prostate Specific Antigen (PSA). Nowadays, some professional societies recommend against using digital rectal exam to search for prostate for cancer. We have found the blood test is more helpful than using our finger to find cancer in average risk men, but the blood test is not perfect either. When receiving your test results, it is not enough to know if you test was “positive” or “negative.” You need to know your number. There are 3 different cut offs you should remember when looking at your PSA results.

When your PSA level is less than 4, this can be thought of as a negative result and your risk of prostate cancer is low. Even more important, is your PSA level is less than 1, your risk of prostate cancer is very low. With this in mind, there is a possibility of having prostate cancer with a level less than 4. Therefore, it is essential to know if your PSA has risen from year to year even if you number is less than 4. If you PSA level is less than 4, but has risen from last year, it is very important that you speak with your doctor to find out if this rise in your PSA should be investigated further.

When the PSA is between 4 to 7, this is a gray zone. There are number of conditions that can cause a rise the PSA level that is not related to cancer. This is includes riding a bike, being intimate or having an infection in the prostate gland. Simply having a larger prostate can lead to a higher PSA level. As a result, when the PSA is between 4 to 7, another blood test should be taken 4 to 6 weeks afterwards to make sure this rise is real. If the blood test remains high, you will need to see a prostate doctor, or urologist.

There is a cut off when we consider a PSA level to be concerning. This is when the PSA level is great than 7, you should be referred to a urologist as soon as possible. There is no need to repeat the blood test before seeing the urologist.

There is controversy around have to best test to find prostate cancer in men. One way is to have a blood test for the Prostate Specific Antigen (PSA). Touching and feeling the prostate has fallen out of favor over time, but this method may be used by your doctor, especially if you are high risk or have a history or prostate cancer. Otherwise, it is important to know your prostate number and when you should see a urologist.

REFERENCES
1. Hoffman RM. Screening for Prostate Cancer. In: UpToDate, Elmore JG & O’Leary MP (Eds), UpToDate, Waltham, MA. (Accessed on October 16, 2021.)