The PSA Screening Controversy

[Tellenbach]

I'm reading "The Great Prostate Hoax" by Richard Ablin. Dr. Ablin, a pathologist, discovered PSA (prostate specific antigen) and he's warning men of the dangers of PSA screening. There are four main arguments against PSA screening:

1. PSA can't diagnose cancer because it is prostate specific, not prostate cancer specific. PSA is present in healthy and cancerous prostates. Furthermore, the level of PSA can be increased by activities such as bike riding, sex, an infection, or an enlarged prostate.

2. People with low PSA levels (0.5 ng/mL) can have cancer and people with high PSA levels (>4 ng/mL) can have no cancer. The current level of concern (4 ng/mL) is an arbitrary value meant to catch "low hanging fruit".

3. The PSA test can't distinguish between aggressive and non-aggressive prostate cancer.

4. Prostate cancer is age related and 65% of men without any symptoms will test positive for prostate cancer when biopsied.

Each year, a million biopsies are performed and 100,000 men undergo prostate removal surgery (radical prostatectomies). The evidence that's trickling out suggests that there is no difference in survival rates between men who get the surgery and men who don't get it.

In 2009, the results of two PSA studies were published in the New England Journal of Medicine:

Mortality Results from a Randomized Prostate-Cancer Screening Trial

This is the major finding:

However, we now know that prostate-cancer screening provided no reduction in death rates at 7 years and that no indication of a benefit appeared with 67% of the subjects having completed 10 years of follow-up. Thus, our results support the validity of the recent recommendations of the U.S. Preventive Services Task Force, especially against screening all men over the age of 75 years.

Prostate removal surgery is no small matter. It causes incontinence (which requires wearing diapers that need to be changed 10 times/day) and impotence in many men.

This is what the US Preventive Services Task Force had to say:

The bottom line is that science tells us there is very little benefit and significant harms associated with mass routine screening. Before a man goes ahead with PSA testing, he needs to be fully aware of what he's getting into, and currently that is not how it's being done. Virginia Moyer, MD

So why do urologists still support PSA screening? It's estimated that half of urology centers would close if not for the profits from prostatectomies.

 

[Kas]

Actually, the at similar time as the trial you wrote about, there was European trial which had completely different results. That’s probably why scientists can’t agree about it. It isn’t proved that PSA works not that it doesn’t. Although European results showed too that due to the PSA tests cancer is overdiagnosed. So some men must be operated so one could live longer.

There are two factors which should make PSA tests have more sense. These are PSA dynamics (because PSA is raising with age- so it should be compared with age norm or previous level) and free:total PSA ratio. (but I’m not sure what are data about them)

And PSA tests are done in age 40-70 now (or shorter if the predicted time of life is less than 10 years) because it’s true that in the age of 70-80years most of the men have cancer, but most likely they won’t die of it.

 

[Tellenbach]

And PSA tests are done in age 40-70 now (or shorter if the predicted time of life is less than 10 years) because it’s true that in the age of 70-80years most of the men have cancer, but most likely they won’t die of it.

Unfortunately, this is not the case in the US. In the Veterans Affairs system, 45% of men over 85 years with 4 or more serious illnesses were still screened with a PSA test according to Dr. Ablin. The book was published in 2014.

So some men must be operated so one could live longer.

I believe the stats are something like: 1 person in 50 is saved by PSA screenings but 49 are not and among those 49, about 5 endure unnecessary and sometimes crippling prostatectomies.

 

[Kas]

Unfortunately, this is not the case in the US. In the Veterans Affairs system, 45% of men over 85 years with 4 or more serious illnesses were still screened with a PSA test according to Dr. Ablin. The book was published in 2014.

That's really shocking. I was talking about european recommendations, but I thought there are similar in US. I'll try to find them...

 

[Kas]

I found this- it was released in 2012

Update of Previous USPSTF Recommendation. This recommendation replaces the 2008 recommendation 38. Whereas the USPSTF previously recommended against PSA-based screening for prostate cancer in men aged 75 years and older and concluded that the evidence was insufficient to make a recommendation in younger men, the USPSTF now recommends against PSA-based screening for prostate cancer in all age groups.
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Recommendations of Others

The American Urological Association recommends that PSA screening, in conjunction with a digital rectal examination, should be offered to asymptomatic men aged 40 years or older who wish to be screened, if estimated life expectancy is greater than 10 years 60. It is currently updating this guideline 61. The American Cancer Society emphasizes informed decision making for prostate cancer screening: men at average risk should receive information beginning at age 50 years, and black men or men with a family history of prostate cancer should receive information at age 45 years 62. The American College of Preventive Medicine recommends that clinicians discuss the potential benefits and harms of PSA screening with men aged 50 years or older, consider their patients' preferences, and individualize screening decisions 63. The American Academy of Family Physicians is in the process of updating its guideline, and the American College of Physicians is currently developing a guidance statement on this topic.

It looks like there are two different recommendations. And statistics you quoted show neither is followed. Quite confusing.

 

[Tellenbach]

There is an Italian study that uses dogs to sniff urine samples for prostate cancer. The dog sniff test is much, much more accurate (90%) than the PSA test.