Controversy Over PSA Screening

PSA Screening | Pacific UrologyBy Stephen Taylor, MD

Urologists have been advocating PSA screening for prostate cancer for more than 20 years. Prostate cancer is the most common cancer in men and the second leading cause of cancer deaths in men, behind lung cancer. In its earliest – curable – stages, prostate cancer is usually completely without symptoms and can only be detected by PSA and occasionally by digital rectal exam.

PSA stands for Prostate Specific Antigen and is a simple non-fasting blood test. PSA is defined by both benign and malignant prostate cells, so all by itself, it does not signal prostate cancer. An elevated PSA blood test can be indicative of prostate cancer, an enlarged benign prostate gland, a prostate infection and other source causes.  An elevated PSA will usually result in a referral to a urologist who will determine the cause of the abnormal test. A digital rectal exam, prostate ultrasound exam, prostate MRI and a prostate biopsy are often necessary to establish the cause and determine whether prostate cancer us present (or if the elevated levels came from another benign cause).

The U.S. Preventative Health Services Task Force has given PSA screening a “D” recommendation based on a single, very flawed study. In the longitudinal study conducted over 10 years, researchers compared men who were assigned to a screening group (of which only 80 percent participated in the screening) versus a group assigned to non-screening (of which 60 percent voluntarily went for screening). They discovered that after 10 years, there was very little decrease in the death rate from “organized” screening.

Prostate cancers typically grow very slowly, and do not cause death for 10 to 20 years. So the 10 year “cut off” was far too short to show a significant decrease in prostate cancer mortality. Moreover, many men who were detected “late” (because of a delay in diagnosis if they were not screened) were caught at incurable stages: alive at 10 years, but suffering the effects of advanced prostate cancer or its treatment.

In the pre-PSA era, 90 percent of prostate cancers were detected at incurable stages. In the PSA era, 90 percent of prostate cancers are detected at curable stages. We know that some prostate cancers grow so slowly that they do not require treatment in men with less than a 10 year life expectancy. These men are usually placed on “active surveillance” where they are monitored for life threatening progression. Young men with over 20 years of life expectancy are offered treatment with curative intent: either total removal of the cancerous gland (robotic radical prostatectomy) or radiation therapy (image-guided radiation therapy).

These new ultramodern treatments both offer very high success rates and very few side effects.  The American Urologic Association’s recommendation is that men should discuss with their urologist whether or not each individual patient is a good candidate for PSA screening based on their life expectancy, family history, co-morbidities (diabetes, kidney failure, severe coronary artery disease, previous stroke, etc.). We believe healthy men should have a baseline PSA when they turn 40, then at intervals ranging from 1-10 years based on the initial value.

Dr. Taylor on KBAY: the PSA Test