A newly published paper has now suggested that data from a single PSA test carried out when the men are between 40 and 64 years of age can be used to project risk for aggressive prostate cancer among African-American men.
These new data come from a study by a collaborative, multicenter team of researchers (see Preston et al.), and the full text of this paper is accessible on line.
The research team used data from the Southern Community Cohort Study (SCCS) to determine whether baseline PSA levels in midlife could be used to predict future risk of prostate cancer, with a focus on aggressive disease. They focused on aggressive disease because the research tram felt that this was the most clinically relevant form of prostate cancer and was less likely to be over-diagnosed than lower-risk forms of prostate cancer.
The data from the SCCS encompassed some 86,000 men and women form the southeastern US. It has the has the highest representation of male African Americans (n = 22 905 men) among all existing cohorts and has a large biorepository.
The research team was therefore able to carry out what is known as a “nested case-control study” of incident prostate cancer that included 766 men selected from among 10,504 black men included in the SCCS who were aged between 40 and 64 years at study entry (between 2002 and 2009) and who (a) gave blood at enrollment, (b) were free of diagnosed cancer at enrollment, and (c) provided informed consent. Recruitment took place at community health centers across 12 southern states.
Among these 766 men, there were
- 197 cases of newly diagnosed, incident prostate cancer
- 569 controls (i.e., men who did not have prostate cancer but who could be matched to the men who did have prostate cancer based on their ages, the dates of blood draw, and the sites of enrollment
What Preston et al. report is the following:
- Average (median) follow-up for all 766 men was 9 years.
- 91/197 cases of prostate cancer met criteria for aggressive disease (Gleason ≥ 7, AJCC stage III/IV, or prostate cancer-specific death)
- Among the 569 controls, the average (median) PSA levels were
- 0.72 ng/ml for men aged 40 to 49 years
- 0.80 ng/ml for men aged 50 to 54 years
- 0.94 ng/ml for men aged 55 to 59 years
- 1.03 ng/ml for men aged 60 to 64 years
- Of all 197 cases with prostate cancer, 95 percent had a baseline PSA level higher than the age-specific median for the controls.
- Of the 91 cases with aggressive prostate cancer, 97 percent had a baseline PSA higher than the age-specific median for the controls.
- For all 197 cases of prostate cancer, the odds ratio (OR) that PSA levels would be in the top 90th percentile as compared to being less than or equal to the median level based on age was
- 83.6 for cases aged between 40 and 54 years
- 71.7 for cases between 55 and 64 years.
- For the 91 cases with aggressive prostate cancer aggressive cancer, the OR that PSA levels would be in the top 90th percentile as compared to being less than or equal to the median level based on age was
- 174 for cases aged between 40 and 54 years
- 51.8 for cases between 55 and 64 years
Looking at these data from a patient perspective, the researchers concluded that:
Prostate-specific antigen (PSA) level during midlife strongly predicted future development of aggressive prostate cancer among black men. Targeted screening based on a midlife PSA might identify men at high risk while minimizing screening in those men at low risk.
Now it is important to understand that this is not a “perfect” study because, for starters, the reasearch team use what is known as a “composite” methodology to define aggressive prostate cancer (as described above).
Ideally, this tool with also need to be validated in an independent group of African-American men, and finding another, large enough cohort of African-American men against which to validate these data could be problematic.
On the other hand, these data do provide us with a reasonable model that confirms the possibility that testing of African-American men when they are as young as 40 years could well help us to identify clinically significant risk for prostate cancer at an early age, which would then increase the opportunity for additional work-up and further testing over time, and early treatment among those at the highest levels of risk.
Filed under: Diagnosis, Living with Prostate Cancer, Management, Risk | Tagged: African=American, black, PSA, risk, testing |
THE "NEW" PROSTATE CANCER INFOLINK 
I remember a long and incredibly boring debate about the definition of African American in this context. I have thought about it a bit in the interim. May I suggest “any man who, in consultation with his doctor, is concerned his ethnic genetic inheritance might predispose him to elevated PCa risk”.
Dear SUM:
I am not writing guidelines. I am reporting on a published article. In this particular article, based on the criteria used in the SCCS, these were all men who self-categorized themselves as either “Black” or “African American”.
If I was writing guidelines, then I still couldn’t use the terminology you are suggesting, because these data don’t necessarily apply to “any man who, in consultation with his doctor, is concerned his ethnic genetic inheritance might predispose him to elevated PCa risk”. They only apply to ones who self-categorized themselves as Black or African American and who were living in 12 southern states in the US between 2002 and 2009.
Please understand that I am not splitting hairs here. These are very important distinctions.