Should different prostate cancer screening guidelines exist for black men?
The excess burden of prostate cancer borne by black men should be an urgent public health priority. Instead, early detection efforts stalled due to avoidable controversies surrounding the risks and benefits of PSA-based screening. Black men are stricken earlier, more frequently and more aggressively than any other group, resulting in twice the mortality rate as white men. There also is well-documented undertreatment of black men with high-risk prostate cancer.
Despite these risks, men of African descent were essentially unrepresented in the PSA screening trials, and study findings likely underestimate the mortality benefits of screening for these men. Recent draft guidelines from the U.S. Preventive Services Task Force called for more research in high-risk groups, but because no randomized trial evidence for this population will be available in the foreseeable future, other forms of high-quality research must be considered. Recent statistical modeling studies and evidence from long-term cohort studies provide compelling evidence that PSA screening targeted to those at high risk (eg, black men and those with family histories), could prevent more cancer deaths when testing is first done early, with subsequent frequency tailored based on the initial baseline test. We believe that black men in particular would benefit from earlier PSA testing. Although the optimal start age is unknown, guidelines from the National Comprehensive Cancer Network and ACS endorse an earlier date of initiation, which likely corresponds to a baseline test at age 45 years. We regard this earlier baseline as part of smarter screening — the purpose of which is early detection of high-risk cancers. This approach is not only feasible and appropriate, it is necessary. On the other hand, multiple recent, large cohort studies — which admittedly include few black men — suggest that if the baseline test result is less than 0.7 to 1 ng/mL, subsequent follow-up testing can be safely deferred for at least 5 to 10 years.
Importantly, decades of research have shown that prostate cancer can be risk stratified at diagnosis with approximately 80% accuracy using clinical parameters alone (eg, Gleason grade, PSA and percentage of positive biopsy cores) — a rate that can increase with emerging imaging, genomic and other tests — and that most low-risk disease does not require immediate treatment. This smarter treatment is based on appropriate risk stratification and default use of active surveillance for most with low-risk disease. Active surveillance is now the preferred standard of care for most men diagnosed with low-risk prostate cancer. Black men comprise relatively small percentages of most surveillance cohorts reported to date, and whether they face higher risks for tumor reclassification and eventual need for treatment remains controversial.
Matthew R. Cooperberg, MD, MPH, is associate professor of urology at University of California, San Francisco. He can be reached at email@example.com. Rena J. Pasick, DrPH, is professor of medicine at UCSF and director of community engagement at Helen Diller Family Comprehensive Cancer Center. She can be reached at firstname.lastname@example.org. Nynikka Palmer, DrPH, MPH, is assistant professor of medicine at UCSF. She can be reached at email@example.com. Peter R. Carroll, MD, MPH, is professor and chair of urology at UCSF. He can be reached at firstname.lastname@example.org. Disclosures: Cooperberg, Pasick, Palmer and Carroll report no relevant financial disclosures.
As someone who investigates prostate cancer patterns of care and outcomes in a racially diverse, military health care system, I have observed racial comparability in prostate cancer aggressiveness at time of detection as well as longer-term outcomes — including disease progression — for black and white patients. One difference we do observe is that black men present with prostate cancer a few years earlier, at a median age of 58-59 years, compared with 62-63 years for white men. However, we examined the rates of metastatic disease at time of initial prostate cancer detection over a 25-year period following the introduction of PSA screening and reported a dramatic decrease in baseline metastases for both racial groups, such that the baseline metastasis-free survival curves for white and black men have become superimposed over time.
Although PSA screening has received much criticism because it is an imperfect tool that leads to overdiagnosis of clinically insignificant disease, it’s compelling that in our racially diverse, equal-access, military health care system, we see highly comparable rates across race of disease aggressiveness at baseline, as well as outcomes along the continuum of cancer care.
Our findings are in sharp contrast to other large national cohorts that show striking racial differences for prostate cancer aggressiveness at time of detection, treatment intensity and outcomes. This has prompted us to investigate whether there are biologic underpinnings to disease outcomes across race and which, if any, biologic differences might be responsible for observed differences in outcomes reported by other national cohorts. There is clear support that access to care, aggressiveness of cancer care, and precancer screening practices can influence disease outcomes in such a way black men shouldn’t need different screening recommendations. There is certainly an argument in both directions, and we don’t know enough to firmly say whether it is mostly biologic vs. social factors that more heavily influence the racial disparity in prostate cancer.
The trickiest age group regarding screening guidelines is men aged 40 to 50 years; there’s more agreement that ongoing, annual screening is not going to benefit patients in that group in terms of long-term prostate cancer mortality reductions. In the short term, it is believed that it merely creates overdiagnosis of clinically insignificant disease. In that regard, we should be looking more carefully at factors that place a man at elevated or unusually higher risk. It could be a lifestyle factor or a strong family history. In fact, instead of making blanket recommendations, the USPSTF has discussed a role for more tailored screening recommendations, not merely based on race but all patient factors. It’s probably more time consuming to do this, but it’s where the field needs to go, with full consideration of patient social and biologic factors, not merely race.
Jennifer Cullen, PhD, MPH, is director of the epidemiologic research program and the Center for Prostate Disease Research, as well as associate professor of the Norman M. Rich department of surgery at Uniformed Services University. She can be reached at email@example.com. Disclosure: Cullen reports no relevant financial disclosures.