Screening strategies could reduce prostate cancer mortality, overdiagnosis among Black men
Of the known racial disparities in cancer incidence and mortality, the disproportionate burden of prostate cancer among Black men remains one of the most pronounced.
According to the NCI, Black men have the highest rate of prostate cancer morality in the United States and are twice as likely as their white counterparts to die of the disease.
“Black men in the United States are about 60% to 80% more likely to be diagnosed with prostate cancer — we know that Black men also are diagnosed at younger ages and more likely to be diagnosed with advanced cancers,” Yaw A. Nyame, MD, MS, MBA, a surgeon and urologic cancer specialist at Seattle Cancer Care Alliance, said in an interview with Healio. “So, if there are tools at our disposal that can help us reduce the burden of Black men dying of prostate cancer — for example, by detecting it earlier — we should use them. I think in prostate cancer, we have that tool in PSA testing.”
However, overuse of PSA screening can lead to overdetection and unnecessary anxiety.
To determine the optimal age range and strategy for PSA screening among Black men, Nyame and colleagues conducted a modeling study, published in Journal of the National Cancer Institute, using two microsimulation models of prostate cancer. Results showed that, compared with historical population screening, annual screening of Black men aged 40 to 84 years would increase mortality reduction — from an estimated 21% to 24% to between 29% and 31% — but greatly increase overdiagnosis per 1,000 men, from an estimated 75 to 86 to between 112 and 129. Limiting annual screening to Black men aged 45 to 69 years would reduce mortality substantially (26%-29%) with a lower overdiagnosis rate (51-61 per 1,000), the researchers wrote.
Nyame spoke with Healio about the methodology of the study, its findings and the importance of reducing prostate cancer mortality while avoiding overdiagnosis.
Healio: How did you conduct your study?
Nyame: This was a collaborative study performed by members of the CISNET prostate cancer group. CISNET is a cooperative group supported by the NCI that uses advanced statistical modeling to project outcomes in several different cancers. I am part of the prostate cancer group, which is led by Ruth Etzioni, PhD, at Fred Hutchinson Cancer Center. Dr. Etzioni and Roman Gulati, MS, also of Fred Hutch, used existing models calibrated to real-world data to project the impact of a variety of screening strategies on prostate cancer outcomes among Black men. Our goal was to determine how much benefit we would gain from increasing screening among Black men, and to estimate the potential harm that strategy could potentially cause. The models use real-world data from the SEER database, the ERSPC trial and other prospective randomized control trials to estimate the impact of more PSA testing among Black men.
Healio: Which early-detection strategies did you test?
Nyame: We looked at various hypothetical situations, including annual screening of Black men between the ages of 40 and 84 years in the U.S. and prostate biopsies for every man with a PSA concentration greater than 4 ng/mL who received a test. We found that although that would decrease the number of Black men who die of prostate cancer, it also would lead to the overdetection of cancers among Black men. We consider these to be prostate cancer cases that would never affect men in their lifetimes. In those cases, men will likely die of natural causes or other causes not related to prostate cancer. So, as a screening strategy, we considered that to be potentially harmful.
We knew from prior studies the group had done that if we restricted the ages at which we screened men, or changed the pattern in which we offer testing, we could significantly reduce rates of overdetection, while potentially while maintaining the benefit of reducing prostate cancer deaths. We ultimately found that if we restricted the age of screening to 45 to 69 years and tested men annually in this hypothetical situation, we would not significantly increase rates of overdetection and still reduce the number of Black men who die of prostate cancer.
The power of this model is that it allows us to study a disease process for which we generally need decades of real-time follow-up. If we instituted this type of protocol among a group of men, it would take between 13 and 16 years to measure that kind of impact. Using the CISNET models, we can use computing power to get reliable estimates of the benefit of increasing prostate cancer screening among Black men. It’s our hope that by using microsimulation, which has been helpful in informing national screening guidelines for other cancers, we can advocate for strategies that might help reduce the burden of prostate cancer in our at-risk populations.
Healio: Are the racial disparities in prostate cancer driven largely by biological differences?
Nyame: That is one of the biggest myths of prostate cancer disparities. Race is a social construct. Social constructs can inform biology, but prostate cancer disparities are not necessarily a phenomenon of inherited risk. We have found many disparities can be explained by differences in the utilization of health care. For examples, studies show that your social strata, whether purely economic or racial, correlates with risk for exposure to environmental pollutants, poverty, access to health care and a variety of other meaningful nonbiologic factors that impact cancer outcomes. Disparities are much more complex than biological risk along and represent a tightly configured relationship between social, environmental, economic, health and biologic factors. In this study, we show that by increasing the utilization of health services, we can reduce disparities in mortality; but, these findings along will not drive the type of outcomes we hope to observe for Black men.
Healio: What is a good strategy for improving uptake of prostate cancer screening among Black men?
Nyame: Screening rates are lower among Black men in general, and a recent study has shown that this gap may have increased after the U.S. Preventive Services Task Force recommendation in 2012 advised against routine PSA screening. That recommendation has since been changed to consider screening as an option for men aged 55 to 69 years, as part of shared decision between men and their physicians.
We recognize that our solution exists in an idealized and hypothetical situation. In reality, we cannot make policy suggestion to simply increase screening as that recommendation doesn’t fix many of the other social issues that may impact an individual’s ability to prioritize their health or access health care services. However, it is also important that we not be deterred by the many challenges we face in our fight to eradicate prostate cancer disparities and death for all men in the U.S. — including our most vulnerable populations.
Realizing changes in screening will require a patient-centered approach that gives Black men, their partners, communities and advocates opportunities to have their voices and experiences drive the interventions and policies we write. Until we give this community space to have their voices heard, I fear that we will have a hard time operationalizing the screening strategies that we modeled.
Healio: What do you have planned next in terms of studying this topic?
Nyame: We recently received a notice of award from the Department of Defense that will support more patient-centered and patient-facing research, with the goal of trying to understand the variety of social, economic, environmental and health factors that may affect the way Black men access screening and treatment. It is our hope that Black men will share their knowledge, attitudes, practices and experiences around early detection and treatment of prostate cancer, and that they will join us as partners in the development of durable solutions to eradicate disparities in prostate cancer.
For more information:
Yaw A. Nyame, MD, MS, MBA, can be reached at 1959 NE Pacific St., Seattle, WA 98295; email: nyuamey@uw.edu.
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