In defence of PSA testing
Last November, in a letter to Barbados TODAY, a group of medical practitioners raised concerns about the method of prostate screening used in Barbados, saying that while the test –– the prostate specific antigen (PSA) –– could detect prostate cancer, the available evidence suggested that very few lives were saved, and screening often led to unnecessary testing and treatment. To support their argument, they referred to the United States Preventative Services Task Force and the Canadian Task Force On Preventative Health Care which do not recommend prostate screening.
However, urologists Dr Jerry Bruce Emtage of Barbados Urology and son Dr Justin Bruce Emtage have insisted that while they do not recommend mass screenings, the PSA test is useful. Below is their full response.
Prostate cancer is very prevalent in Barbados. It seems to be affecting younger men. Stage at presentation is often very high. Grade of disease very high.
The above is exactly what portends across the black Caribbean and African American male population. The American National Task Force came up with a set of guidelines, and these guidelines were referenced to individuals with low risk. The Canadian Task Force refers exclusively to the white male population and therefore has no reference or basis for the black Caribbean or African American male.
If you are a black male over 40, you are at high risk.
No one has ever suggested that PSA testing should be used for mass screening. The most recent American Urological Association guidelines speak to the use of PSA in high-risk groups. These high-risk groups refer to individuals who in spite of racial origin have first or second generation family members with a history of prostate cancer and the African American male.
The other point with regards to prostate cancer is that we have no way of predicting the biological behaviour of the cancer. It would be nice if we could say to a patient: “You have prostate cancer diagnosed by ultrasound and biopsy, but the markers on your cell wall suggest that this is non-progressive.”
That would be ideal, but such does not exist.
Doctors cannot expect patients to play Russian roulette with themselves. The black male is at greater risk with watchful waiting approach/surveillance protocol. The general public should also be aware that the urologist has a number of tests, available to assist in assessing the significance of an elevated PSA.
1. PSA as tested is total PSA. One can also ask for a free PSA level and then calculate the percentage free of the total. Percentage free/total PSA <10 is significant and suggests possible prostate cancer. It does not mean prostate cancer.
2. PSA density. This is calculated based on the prostate volume as acquired at the time of the transrectal ultrasound. Total PSA/prostate volume –– if this is <0.15 and the scan looks normal, then there is no need for biopsy.
3. PSA velocity. This refers to the rate of change of total PSA over given time. The accepted PSA velocity is 0.75ng/ml /year. Increasing rate or change of PSA velocity suggests aggressive disease.
4. In my centre, patients with suspected PSA elevations also have available to them the PCA 3 test. The specimen is urine collected post-prostatic massage. I do this in conjunction with the University of Michigan. PCA 3 is a urine test that increases PSA specificity.
Investigators identified and characterized PCA 3 by differential display as a non-coding RNA that was highly over expressed (10-100-fold) in prostate cancer as opposed to non malignant/benign tissue.
5. PHI test. Several studies have demonstrated improved performance characteristics for the detection of prostate cancer when comparing PCA 3 to Total PSA. PCA 3 has a higher accuracy for prostate cancer detection compared to PSA. However there is insufficient evidence that primary screening
with PCA 3 would improve health outcomes.
6. Other test –– looking at different isoforms of PSA such as [-2]ProPsa. PCA 3, PHI Test, PSA isoforms
are all more expensive than the PSA. Therefore, with the above, the urologist can manage elevated PSA levels with discrimination. To get back to the topic at hand consider the sentiments expressed by the current literature.
The Journal Oncology –– Active Surveillance For Low-Risk Prostate Cancer In African American Man: A Multi-Institutional Experience. Conclusion: Our study suggests a higher disease progression rate in the African American male who chooses active surveillance for low-risk prostate cancer compared with the non-African American male, signifying a potential need for closer follow-up and more stringent enrolment criteria in the African American male. (Urology 83:364-368, 2014.)
The above article points to the aggressive nature of this disease in both the black American and the black Caribbean male. Again, we have no way of making the distinction as to whether a patient’s disease is going to be progressive or not. And the rule of thumb therefore has to be that all black men run the risk of dying from this disease.
This does not apply to the black man 80 years of age.
Pathological Outcomes And Biochemical Recurrence-Free Survival After Radical Prostatectomy In African American, Afro-Caribbean (Jamaica) And Caucasian American Men: An International Comparison. British Journal Of Urology International 2012 (111, E186-E190). Conclusion: This international comparison of the clinicopathological outcomes in African American, Afro-Caribbean and Caucasian American men undergoing radical prostatectomy shows that African American and African Caribbean men present similarly with more aggressive disease features than Caucasian men and have lower five-year BCR-free survival.
This publication highlights the aggressiveness of prostate cancer at presentation of both the African American and the Afro-Caribbean male.
American Urological Association (AUA) –– guidelines statements:
1. The panel recommends against PSA screening in men under age 40 years. 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. (And we agree with the above.)
2. The panel does not recommend routine screening in men between ages 40 and 54 years at low or average risk. For men younger than age 55 at higher risk (for example, positive family history or African American race/African Caribbean), decisions regarding prostate cancer screening should be individualized. The above articles and the AUA guidelines exaggerate the false arguments from both the task force in America and the task force in Canada. (Studies primarily based on the Caucasian male.)
The tragedy that prostate cancer presents in our population is significant. The travesty is that general practitioners are not on the front lines of this disease. They do not deal directly with patients who are confronted with the futility of metastatic (spread) prostate cancer and the great expense required in treating it. Current medications for individuals with hormone refractory prostate cancer, that is, cancer no longer responding to current medications are Abiraterone and Entalzumid.
These can cost anywhere between $15,000 and $20,000 a month. Provenge can run to almost US$90,000 a month. How many in our population can afford this treatment? It is therefore cheaper to find these individuals early rather than late.
Late diagnosis, with increased morbidity and mortality, was what I found when I returned to this country in 1990. We should not go back to that. There are minimally invasive techniques available which in the right patient can give the same benefit as surgery without the morbidity.
People with high-grade, high-volume disease are always best served with surgery. Selection is the key in treatment decision. As a people we clearly have a very high incidence of this disease.
Recent data being readied for publication from my centre shows the rate may be as high as 115/100,000 –– one of the highest in the world. The incidence in “the black male” is three times that of the Chinese male, two to three times that of the Caucasian/Indian male.
Oft-times these three groups have absolutely no first-hand experience of a family member with this disease.
We all do! We have friends and family stricken by this disease. We cannot extrapolate from a Canadian or North American experience; we have to find our own.
The minimum standard is for general practitioners in this country to discuss PSA testing with all of their black male patients over 40 years and Caucasian males over 50. The decision as to whether it is done or not will always rest with the patient.
Let it be made clear, no one is suggesting mass screening! We should not go back to the Dark Ages where the young and middle-aged black men present with cancer that has spread and the only option for treatment available to them is palliative (no hope for cure).