Dear OncoLink "Ask the Experts,"
Would you please address the issue of rising PSA levels further? My father had a radical prostatectomy, but his PSA level never registered 0. He had radiation therapy about a year ago, and once again his PSA level never fell to 0. His PSA is up to 3.3 ng/mL now. A bone scan last summer didn't indicate any presence of cancer cells. He will have the results of another bone scan next week. What questions should he be asking his urologist? A general practitioner told him the PSA results could be false, but I find this hard to believe when the levels have responded to treatment somewhat.
Neha Vapiwala, MD Senior Editor of OncoLink and Assistant Professor in the Department of Radiation Oncology at the Hospital of the University of Pennsylvania responds:
Prostate specific antigen, or PSA, is a glycoprotein produced by the epithelial cells in the glands and ducts of the normal prostate gland as well as by prostate cancer cells. Therefore, serum PSA is prostate-specific, not prostate cancer-specific. The fact that your father had a radical prostatectomy means that his PSA should register as zero or undetectable (most labs will state that the PSA level is somewhere below the detectable range, usually less than 0.2 ng/mL), since the surgery should have removed all of the prostate gland along with the cancer.
Serum PSA can be elevated for a number of reasons: benign prostatic hypertrophy (BPH), prostate infection, prostatic manipulation or biopsy, and prostate cancer. In your father's case, PSA elevation could only be due to residual cancer, since there is no longer a prostate there to be enlarged, infected, or manipulated. Most PSA elevations after radical prostatectomy can be treated with local radiation therapy to the prostate bed (the surgical area from which the prostate was removed) with varying degrees of success. Some advocate the use of anti-androgen therapy (hormonal therapy - Zoladex, Lupron, Casodex, Flutamide, etc.) along with, after, or instead of radiation therapy, all depending on the specific circumstances of the case.
The fact that his PSA remains elevated after radiation therapy is of significant concern. It is highly suggestive of residual cancer in the prostate bed, lymph nodes, or bones. While bone scans are helpful in localizing metastatic disease (spread of cancer) in the bones, they do not always detect disease. No radiographic study is 100% sensitive and accurate. Your father may have disease that is too small to detect on bone scan. One important issue is whether your father has any new bone pain, which could be a sign of disease spread. One issue you should discuss with your father's urologist is whether your father needs hormonal therapy at this time.