A few things to consider, taken from lab tests online.
During treatment for prostate cancer, the PSA level should begin to fall. At the end of treatment, it should be at very low or undetectable levels in the blood. If concentrations do not fall to very low levels, then the treatment has not been fully effective. Following treatment, the PSA test is performed at regular intervals to monitor the person for cancer recurrence. Since even tiny increases can be significant, those affected may want to have their monitoring PSA tests done by the same laboratory each time so that testing variation is kept to a minimum.
A relatively new test called "ultrasensitive PSA" (USPSA) has been reported. It has been suggested that this test may be useful in monitoring for persistence or recurrence of cancer after treatment. This test detects PSA at much lower levels than the traditional test. It has been suggested that increases in PSA due to the persistence or return of cancer can be identified much sooner with this test. However, results of this test must be interpreted with caution. Because the test is very sensitive, there can be an increase in PSA levels from one time to the next even when no cancer is present (false positive).
^ Back to top
Is there anything else I should know?
Since the DRE can cause a temporary elevation in PSA, the blood is usually collected prior to performing the DRE.
Prostate manipulation by biopsy or resection of the prostate will significantly elevate PSA levels. The blood test should be done before surgery or six weeks after manipulation.
Rigorous physical activity affecting the prostate, such as bicycle riding, may cause a temporary rise in PSA levels. Ejaculation within 24 hours of testing can be associated with elevated PSA levels and should be avoided.
Large doses of some chemotherapeutic drugs, such as cyclophosphamide and methotrexate, may increase or decrease PSA levels.
In some men, PSA may rise temporarily due to other prostate conditions, especially infection. A recent study found that in about half of men with a high PSA, values later return to normal. Some authorities recommend that a high PSA should be repeated, between 6 weeks and 3 months after the high PSA, before taking any further action. Some physicians will prescribe a course of antibiotics if there is evidence that there is infection of the prostate.