Controversy in Prostate Cancer Screening
The US Preventive Services Task Force ignited a firestorm of controversy within the medical community by announcing that the PSA (prostate specific antigen) blood test should no longer be recommended as a routine screening tool for detection of prostate cancer. However, many patient advocacy groups and physicians disagree with the proposed guideline change.
Citing 5 large clinical trials the USPSTF drew the conclusion that the PSA test does not save lives and leads to expensive and unnecessary testing. Only one of the 5 studies reviewed showed a reduction in prostate cancer mortality in screened versus unscreened men, with a modest benefit of reducing risk by 0.07%, and only in men age 55-69. The other studies found no benefit but did reveal false-positive rates of 12-13%.
I still recommend the PSA test for men. Having had numerous cases in which the test led to an early diagnosis of prostate cancer, I can’t see the sense of just stopping the testing altogether. But, like other physicians, I do have criticism of the manner in which PSA testing and management is done.
Prostate cancer is something that most men will get. Autopsy studies reveal that 2/3 of men will have a prostate cancer by age 90. These men will die of something else, but the cancer is present. It is usually a slow growing cancer and not a concern for most elderly men. If left untreated the typical prostate cancer will cause death 8-10 years after the initial diagnosis. Since it most commonly presents later in life and is so slow growing, there is indeed reason to defer testing at a certain age. But it can strike at a young age, is usually cured if found early, and thus the case for screening.
About the PSA Test
PSA is a protein that is normally made by prostate tissue and is found in the bloodstream in healthy men. The normal range is between 0 and 4 ng/mL (nanograms per milliliter of blood). Levels over 10 are associated with cancer about 66% of the time. The difficult result to interpret is when PSA is in the “gray zone” between 4 and 10, causing concern but only being associated with cancer about 25% of the time. The conundrum is then how to select out the men who really have underlying cancer, without over-diagnosing the men without cancer.
The main way to diagnose prostate cancer is to get a tissue sample. A prostate biopsy is done using an ultra-sound for guidance and inserting a specialized needle into the prostate. The needle needs to go through the rectal wall and down into the prostate. Typically biopsies are taken from each quadrant of the prostate to get a total of 8-16 tissue samples. The most common side effects of the biopsy are discomfort, pain, or infection. Causing unnecessary fear of cancer is of course a concern for the men with an elevated PSA that leads to a negative biopsy. This would be the 12-13% rate of “false positives” in which the PSA suggests cancer but none is subsequently found.
The PSA level is proportionate to the size of the prostate, thus an enlarged prostate will produce more PSA. Inflammation or infection of the prostate will also cause an increase in PSA. Activities such as riding a motorcycle, bike or horse, heavy lifting, or bouncing around on a tractor seat, can all cause elevations in PSA. Even sexual activity or a simple DRE (digital rectal exam) of the prostate can cause a rise in PSA levels.
When the PSA level falls between 4 and 10 the “free” PSA can help determine which patient is at highest risk for cancer. The unbound or “free” portion of the PSA is lower with cancer so the lower the “free” portion the higher the likelihood that cancer is present. When the “free” PSA is low then a biopsy may be the best course. If the “free” PSA portion is high, cancer is less likely, and a biopsy may not be indicated.
Newer urine tests, such as the “PCA3” can detect proteins associated with prostate cancer. After a DRE in which the doctor purposefully pushes firmly on the prostate, up and down the sides several times, cancer related proteins may be expressed into the urinary tract and detected in a urine sample. If positive then this would then lead to a biopsy for more details. If negative then a biopsy may not be indicated.
The absolute PSA number is only part of the result. Other factors such as how fast the PSA is rising help to determine when cancer is present. The “PSA velocity” is the rate of increase over time and an increase of 0.75 per year is considered suggestive of cancer. The “doubling time” is another version of PSA velocity and is the time it takes the PSA to double. With aging the PSA normally increases so a level of 1 may be reassuring to a 50 year old, while a level of 2-3 is normal in an 80 year old.
Using an ultra-sound to determine the size of the prostate is a simple and valuable way to calculate the “PSA density”. A larger prostate will normally produce more PSA, while a smaller prostate will produce less PSA. The PSA density can help adjust the PSA to the size of the prostate.
Blood sampling for cancer cells
Technology now allows us to draw blood and look for “circulating tumor cells” that arise from most cancers. RGCC is the lab we use and I’ve used this testing several times in men to help shed light on the presence or absence of prostate cancer. For prostate cancer we’d use the Oncotrail Prostate test. For uncertain primary cancer or general screen we might use the Oncotrace test.
As an example, I have a patient who was getting an annual prostate biopsy due to a very strong family history of prostate cancer. Every year negative biopsy results, but the patient wanted a simpler and less painful way to screen. The Oncotrail test was negative reassuring him no cancer was present. Another patient had a rising PSA that was suspicious for cancer and the Oncotrail test was positive confirming cancer without the need for biopsy.
Who to Screen with PSA
Since prostate cancer is rare in men under age 50 the PSA test is not recommended until age 50 unless there is a family history of prostate cancer at a young age. For example, if your father or brother had prostate cancer at age 55, then screening might start 10 years earlier around age 45.
As prostate cancer is so common with aging there is a point when we might stop screening. Rather than use age, I consider a man’s overall health. If a patient has serious health problems that are likely to cause death within the next 5-10 years or so, such as severe heart disease, then it may be time to quit worrying about prostate cancer as it would be very unlikely to be the cause of death. On the contrary, if I have a very healthy 80 year old who may well live to 100, then screening for prostate cancer makes sense as this patient might well die from prostate cancer diagnosed at age 80. Also, even if my 90 year old patient is obviously not going to treat prostate cancer, I still want to know if it is present so as to manage issues that might arise.
How to Manage PSA Results
If the PSA is elevated the first consideration is causes for a false elevation. Simply repeat the test in 4-6 weeks and be sure to avoid activities (noted above) that may cause a false elevation. If repeat testing is still elevated then I might empirically treat for prostate infection which is fairly common and can “simmer” along without many symptoms. After a round of antibiotics a repeat PSA is often back to normal. If the PSA elevation persists after all this, then checking a “free” PSA level and the PCA3 urine test may be in order. If these are reassuring then it may be prudent to just repeat the testing every 6 months or so to see if the PSA level remains stable. Finally, an ultrasound examination of the prostate may reveal areas of increased density or blood flow that suggest cancer.
Last, when the PSA testing does lead to a positive biopsy and diagnosis of cancer, great care needs be taken in considering what type of treatment, if any, is indicated. There are numerous options for successful prostate cancer treatment and patients are best served when they take the time to carefully consider their choices. Sometimes aggressive treatments are clearly indicated and other times “watchful waiting” is the best course.
I still think the PSA test is a good screening test, but only when accompanied with patient education about the limits of the test, followed by strong patient-physician scrutiny in the interpretation and management of the results.
Scott Rollins, MD, is Board Certified with the American Board of Family Practice and the American Board of Anti-Aging and Regenerative Medicine. He specializes in bioidentical hormone replacement for men and women, thyroid and adrenal disorders, fibromyalgia and other complex medical conditions. He is founder and medical director of the Integrative Medicine Center of Western Colorado (www.imcwc.com) and Bellezza Laser Aesthetics (www.bellezzalaser.com). Call (970) 245-6911 for an appointment or more information.