PROSTATE SPECIFIC ANTIGEN (PSA)
Prostate specific antigen (PSA) is a substance produced by the prostate gland and is secreted in semen. Elevated PSA serum levels may be an indication of prostate cancer, but it may be due to a noncancerous condition such as prostatitis or benign prostatic hyperplasia.
ARE THERE NORMAL VALUES?
Most men have levels of PSA below 4 (ng / mL) and this has traditionally been used as the threshold for concern about the risk of prostate cancer. Men with prostate cancer often have PSA levels greater than 4, although the cancer may occur in any PSA level.
According to published studies, men who have prostate gland soft during the digital rectal examination and
- PSA less than 4 have only a 15% chance of having prostate cancer.
- Those with PSA between 4 and 10 have a 25% chance of having prostate cancer.
- In PSA greater than 10, the risk increases and may be as high up to 67%.
In the past, most experts mentioned PSA levels below 4 ng / mL as normal. Given the findings of the most recent studies, some recommend lowering of thresholds that determine whether a PSA test is normal or increased. Some researchers encourage the use of the threshold of less than 2.5 or 3 ng / mL for normal prices, particularly in younger patients. Younger patients tend to have smaller prostates and lower PSA values, so any increase in PSA in younger more men than 2,5 ng / ml is a cause for concern.
It is important to understand that the PSA test is not perfect. Most men with elevated PSA levels have benign prostatic hyperplasia, which is a normal part of aging.Conversely, low levels of PSA in the bloodstream, does not exclude the possibility of prostate cancer. However, most cases of early prostate cancer were found to have a high PSA blood test .
DOES THE ANNUAL GROWTH OF PSA MATTER?
Equally important as the PSA value is the velocity (although rising, how fast and for how long). An increase up to 0,75 ng / ml per year is not considered particularly worrying.
WHEN SHOULD I HAVE A PSA?
The American Cancer Society says that men should consult with their doctor about the benefits, risks and limitations of prostate cancer screening before deciding whether it should be done. The guidelines make clear that the prostate specific antigen (PSA) in blood should not be made unless this debate happen.
They recommend that most men with average risk for prostate cancer, visit the urologist at the age of 50 years and those with higher risk (positive family history) for prostate cancer should go earlier.
PSA testing in men younger than 40 years is not recommended.
The routine PSA test is not recommended for men with a life expectancy less than 10-15 years.
WHY CAN A PSA BE HIGH?
Elevated PSA levels may indicate:
- Cancer of the prostate.
- Benign prostatic hypertrophy.
PSA levels can also be affected by other factors:
- Age. Your PSA will normally go up slowly as you age, even if you have no problems with the prostate.
- Medicines. Some medicines can affect PSA levels in the blood. Tell your doctor if you are taking finasteride (Proscar) or Dutasteride (Avodart).
WHAT WILL MY DOCTOR PROPOSE IF PSA IS HIGH?
If your PSA level is high, your doctor may recommend that you get a prostate biopsy to check for cancer .
ANY ALTERNATIVE TESTS FOR PSA?
There are some new PSA tests that can help you and your doctor determine if you need a biopsy.
Free PSA (PSA free) and PSA ratio:
The PSA takes two principal forms in the blood. One is connected by blood proteins and the other circulates free. The PSA ratio test shows how PSA circulates freely relative to the overall level of PSA. The proportion of free PSA is lower in men who have prostate cancer than men who do not.
Studies show that if the results of your PSA are on the borderline range (4-10), a low percentage-PSA free (less than 10%) means that the chance of having prostate cancer is about 50% and that you should have a biopsy.
Many doctors recommend biopsies for men whose PSA ratio is 20% or less.
The PSA velocity is not a separate test. Rather, it is the change in PSA levels over time. Even when the total value of PSA is not higher than 4, a high PSA velocity (increase of more than 0,75 ng / mL in one year) suggests that cancer may be present and a biopsy should be scheduled.
Examination PCA3 urine.
This urine test is a more sensitive but very expensive method to take the decision to biopsy.