Friday, May 31, 2013

PSA Issues Keep Returning



The Trustees of SSI and Medicare have just issued their annual report on the health of that system[1]. Needless to say the system faces challenges, substantial challenges. The ACA proposes various ways to manage them and for better or worse it is rationing. Not a direct and blatant form of rationing but a more subtle and possibly sinister form which is the result of “new” or “updated” clinical testing regulations. At the heart of this is the PSA issue.

The AUA has issued a new set of guidelines which put additional pressure on PSA testing[2]. The recommendations are as follows:

1. The Panel recommends against PSA screening in men under age 40 years. (Recommendation; Evidence Strength Grade C) In this age group there is a low prevalence of clinically detectable prostate cancer, no evidence demonstrating benefit of screening and likely the same harms of screening as in other age groups.

2. The Panel does not recommend routine screening in men between ages 40 to 54 years at average risk. (Recommendation; Evidence Strength Grade C) For men younger than age 55 years at higher risk (e.g. positive family history or African American race), decisions regarding prostate cancer screening should be individualized.

3. For men ages 55 to 69 years the Panel recognizes that the decision to undergo PSA screening involves weighing the benefits of preventing prostate cancer mortality in 1 man for every 1,000 men screened over a decade against the known potential harms associated with screening and treatment. For this reason, the Panel strongly recommends shared decision-making for men age 55 to 69 years that are considering PSA screening, and proceeding based on a man’s values and preferences. (Standard; Evidence Strength Grade B) The greatest benefit of screening appears to be in men ages 55 to 69 years.

5. The Panel does not recommend routine PSA screening in men age 70+ years or any man with less than a 10 to 15 year life expectancy. (Recommendation; Evidence Strength Grade C) Some men age 70+ years who are in excellent health may benefit from prostate cancer screening.

Simply stated the guideline limits testing to men 55 to 69 years of age. It does not recommend testing for men over 69 years of age, the age at which most prostate cancer occurs.

Now the evidence used which I have reviewed in my work on Prostate Cancer Genomics[3] demonstrates the clear problems with the major studies, problems that many in the field have recognized and thus in a similar fashion discount the study out of hand. Thus the basis for these recommendations is highly tainted and suspect.

Now in a paper written for the magazine Columbia Medicine, the alumni magazine for P&S grads and affiliates, the author states[4]:

The PSA controversy exploded in May 2012, when the U.S. Preventive Services Task Force gave the test a resounding "D" grade, recommending against its use as a screening tool. The independent panel of experts in prevention and primary care (no urology or oncology experts were on the panel) found that the test led to "overdiagnosis" of prostate cancer and, consequently, overtreatment. For Dr. Benson, as for many urologists across the United States, that line of thinking is unworkable on multiple levels. "There's no such thing as overdiagnosis; there's only overtreatment," he says. "And you can't decide whom to treat and whom not to treat, you can't establish risk, without diagnosis. So the concept of overdiagnosis is dangerous, and it will preclude patients from getting life-saving therapy when it's indicated."

Dr Benson is head of Urology at Columbia University Medical Center and a world expert in treating this disease. I know the group there quite well and Benson and his team are truly world class. Benson is at the forefront of the battle. The article continues:

Dr. Benson stresses that the overall boundaries are clear. "The goal for prostate cancer treatment is death from something else," he says. "Prostate cancer is, in general, a slow growing cancer, so to take an 85-year-old man with a PSA of less than 4 and say he needs ongoing PSA screening is insane. But to take an 85-year-old man who has never had a PSA ever in his life and say he shouldn't get one, just to see where he's at, is also crazy. I think every man, regardless of age, deserves one PSA. If that one PSA places you in a category where the chance of your dying of prostate cancer is low, then you don't need to have biopsies and additional PSA testing. This is a $15 blood test. The rub here is not in the PSA; the rub is in what people do with the data."

Benson is also quoted as follows:

One of the department's most interesting areas of current research is in confirmatory biopsies to decide eligibility for active surveillance among men who come to Columbia after being diagnosed elsewhere. "I have greater confidence in our ability to thoroughly biopsy the prostate," says Dr. Benson, who performs biopsies with 24 to 30 cores rather than the more typical 12. To test the accuracy of initial biopsies at other facilities and consequent eligibility of patients for active surveillance, Dr. Benson selected 60 incoming patients and, before enrolling them in active surveillance, repeated their biopsies to be sure that the original tests hadn't missed prostate cancer that might be of greater risk.

This is a critical difference, namely the increased core density. We have demonstrated the probability of detection versus number of cores, and also total prostate volume. Going from the old six cores to 24 dramatically increases the detection probability, especially is using trans-rectal ultrasound guiding by ax experienced urologist. The difference between a procedure at Columbia versus at some local clinic can be orders of magnitude in terms of detection probability. Also the sequelae problems are generally much lower, even with more cores.

Finally Benson states:

For Dr. Benson, his current touchstones show the way forward. "There are two telling statistics," he says. "One is that before PSA screening, the most common presentation was a patient with metastatic disease. And the second thing is that metastatic disease is normally rare and the death rate has been reduced by 40 percent. What we have to do is find ways of continuing to have a death rate reduced by 40 percent while not treating people who don't need treatment. That has to be the goal."

Eliminating a test which has a false alarm rate is clearly NOT the way to go, it is especially not the way if we want an informed patient as part of the decision process.

The problem here is that PSA measurements and other types of non-invasive measurements are critical and especially if we have temporal data for the patient, namely annual or even semi-annual PSA tests along with %Free PSA, and we can calculate velocity and other measures, normalize them for Prostate volume, then we have a substantially better test. Combine that with competent and experienced urologists and biopsies then we can ascertain what the true state of reality is.

Having some panel decide based on faulty data is NOT the way to proceed.
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