Prostate specific antigen (PSA) is a protein produced by the prostate gland. It is measured in the bloodstream and is a useful tool for keeping track of men who have been treated for prostate cancer. Does an elevation of PSA after radiotherapy, be it a prostate implant and / or external beam radiotherapy, always mean the recurrence of the disease?
In the past, a rise in PSA after a prostate seed implant or external beam radiation therapy was considered a harbinger of a prostate cancer relapse, often leading to expensive tests and invoking a great deal of anxiety in the patient. . Then, when the PSA level rose to 10 ng / ml or more, the men received hormone therapy. Since the latter is associated with a number of unpleasant side effects, it is desirable to refrain from using hormone therapy unless necessary. So the question arises: when does an increase in the PSA level not mean that the cancer has returned?
There is a phenomenon known as PSA rebound, in which the PSA level rises between one and three years after the man has completed radiation therapy. The PSA level eventually returns to the baseline that it reached just after treatment. The rebound of PSA may be due to the death of damaged cancer cells that release their PSA.
A PSA rebound usually begins with a less than one point increase (less than 1 ng / ml) in the PSA level. Also, PSA rises after three years are less likely to be part of a rebound and, unlike a rebound, PSA rises by more than 1.2 ng / mL are less likely to revert to fall back to your starting points.
A recent study collected data on 7,500 men who were treated for prostate cancer with radiation therapy. Almost half of these men were found to have a PSA rebound. However, there were no adverse effects on their survival. In fact, these men did just as well as the men whose PSA did not rebound. Also, patients who show such a PSA rebound less than two years after treatment may be less likely to have the cancer come back later.
More good news is now that doctors know that a rise in the PSA level does not necessarily mean that the prostate cancer has recurred; men whose PSA rebounds after radiation therapy can be monitored by their doctors, who may repeat the PSA blood test six months later.