The Problematic PSA

There has recently been much debate and discussion as to whether or not the PSA blood test should be used in screening for prstate cancer.  The PSA is a blood test.  It stands for "prostate specific antigen."  Protein particles in the prostate gland are released in small quantities into the blood stream and have found to be elevated in prostate cancer, a state in which prostate cells are multiplying and dividing at an accelerated rate.  Since the development and routine use of this test, the detection of prostate cancers has increased dramatically.  What is not clear, though, is whether increased detection has led to saved lives.  Let me discuss further some of the controversies that surround the issue.

First, the test itself is not a perfect test.  Cancer is not the only cause of having an elevated blood test.  A lower urinary tract infection may also elevate the test.  Some may have a low grade inflammation of the prostate gland (chronic prostatitis) that will lead to having an elevated PSA.  Recent sexual intercourse can cause transient elevations in the PSA as well.  If an abnormal result is found, it is important to repeat the test in 6-12 weeks prior to considering a prostate biopsy, a rather invasive and not so pleasant procedure.

Proper interpretation of the PSA is very important.  The test itself is not dangerous, but an elevated result may lead to a path consisting of first a biopsy and, if cancer is found, to possibly surgery, castration chemotherapy or radiation.  Any of these three may carry adverse effects ranging from urinary incontinence, urinary frequency, impotence and bloody diarrhea.  Though prostate cancer is the leading cause of cancer, it is far from the leading cause of cancer death.  Most prostate cancer is a slow growing process that most people will die with rather than from.  However, there are cases that can be more rapidly progressive and deadly.  In this form, the cancer can spread to other organs in the abdomen and into the bones.  At this stage, the cancer is quite difficult to treat.  The demise is usually slow, painful and progressive.  When looked at as a whole, the vast majority of patients will not have this deadlier version.  Some will interpret those statistics in such a way as to conclude that early detection of prostate cancer is not worth the complications attendant to its treatment.

What is really needed is a way to determine who will progress to the deadlier form of disease and who will not.  In such an instance, treatment could be safely withheld from those who do not need it but could be aggressively applied to those who do.  We do not as yet have such markers.  Strides in this area are being made in relation to breast cancer but are lacking as of yet for prostate cancer.  In the meantime, proper interpretation of the PSA test can help guide decision making.  This should be done on an individual basis between each patient and their physician.

I personally feel that it is appropriate to screen patients with a PSA level in their forties, especially if there is a family history of prostate cancer.  If in the forties, the PSA is low (below 1.0 ng/ml) waiting an additional five years to repeat the test is reasonable.  I recommend yearly testing in someone who is in their 50's.  In the 40's and 50's, an elevated test should first be repeated to make sure that it is accurate.  I am more aggressive in this age group since detection is much more likely to result in meaningful treatment.

As a patient enters their 60's and 70's, I look less at the absolute value of the test and more at how it is changing.  The PSA will rise with age just due to the fact that the prostate never quite stops growing.  If, through the years, there has been a slow gradual increase, I am not nearly so concerned as someone who suddenly has a steep spike in their value from one year to the next.  If repeat testing at a shorter interval shows progressive worsening, that is likely a sign of progressive disease and warrants consideration for a biopsy.  In a patient in his 80's or 90's, I would only use an elevated PSA if I thought there was progressive disease as manifested by symptoms of urinary blockage or evidence of cancer in the bones.

One comment.  The above discussion applies only to patients not previously known to have prostate cancer.  In a patient with known cancer, who has been treated, the PSA is a good marker of disease activity and there is no controversy as to its use.

Lastly, a word about treatment.  Hormonal based treatments definitely have symptoms of weakness, fatigue and hot flashes that likely will occur.  Radiation treatments have evolved so as to be more precise and involve less damage to other nearby organs (such as the large bowel and bladder).  In this instance there is less diarrhea, rectal bleeding and frequent urination.  Surgical techniques have changed considerably.  Many urologist have become quite proficient in the use of robotic procedures.  Since the prostate lies deep in the pelvis, former surgical techniques did not allow the surgeon to always see what was being stitched or cut, but was done by feel alone.  The robotic techniques allow for much better visualization of the area and much more precise stitching.  In the right hands, such a surgery has a very low incidence of impotence and incontinence.  Further studies are being done to determine if these better techniques can result in prolonged life without sacrificing the quality that we want.

In conclusion, using the PSA test to screen for prostate cancer is not a black and white issue.  Ask your doctor for his opinion.  Consider your options and choose the course that you feel most comfortable taking.