A prostate specific antigen (PSA) is a protein produced by the prostate gland. It is measured in the bloodstream and is a useful tool for men who have been treated for prostate cancer. Does an increase in PSA after radiation therapy, whether a prostate seed implant and / or external beam radiation therapy, always mean a relapse of the disease?
Previously, an increase in PSA after implantation of a prostate semen or radiation therapy to an external beam was considered a precursor of recurrent prostate cancer, which often caused expensive tests and caused great anxiety for patients. Then, when PSA levels rose to 10 ng / ml or higher, men were placed on hormone therapy. Since the latter is associated with a number of unpleasant side effects, it is desirable to abandon the use of hormone therapy without the need. The question then becomes: when does an increase in PSA level mean that the cancer has returned?
There is a phenomenon known as rebound PSA, in which the PSA level jumps up within one to three years after a person has completed radiation therapy. PSA levels historically return to baseline levels achieved immediately after treatment. The rebound of PSA can be caused by the death of damaged cancer cells that release their PSA.
PSA rebound usually starts with less than a single point (less than 1 ng / ml) increase in PSA. In addition, an increase in PSA after three years is less likely to be part of a rebound, and, unlike a rebound, an increase in PSA levels of more than 1.2 ng / ml is less likely to return to baselines.
A recent study collected data on 7,500 men who were treated for prostate cancer with radiation therapy. It was found that almost half of these people had a PSA rebound. However, there was no adverse effect on their survival. In fact, these people are just as good as the men who did not jump PSA. In addition, patients who show this PSA rebound less than two years after treatment may be less likely to return the cancer later.
The better news is that doctors know that an increase in PSA does not require the reappearance of average prostate cancer, men whose PSA rebounds after radiation therapy may be followed by their doctors, who can repeat a PSA blood test after six months.
