The PSA level is expected to decrease to almost zero a few months after a prostatectomy, according to the American Cancer Society. Doctors generally recommend checking the PSA level on the sixth to eighth week after the surgery, because some PSA may still remain in the blood after the prostatectomy.
A significant level of PSA detected doesn't necessarily mean that it is because of cancer cells, states the American Cancer Society. Doctors usually advise monitoring the patient's PSA level over time to see if it is rising and to give further diagnosis or treatment from there.
A significant PSA level after a prostatectomy can be attributed to cancer cells again or other factors, explains the Mayo Clinic. It may be due to the remaining prostate tissue, which releases PSA into the blood. It may also be brought on by prostatitis or the inflammation of the prostate tissue.