Black men at greater risk for preclinical prostate cancer, metastatic progression
An estimated 30% to 43% of black men develop asymptomatic prostate cancer by the age of 85 years, making them 28% to 56% more likely to develop preclinical prostate cancer than men of other races, according to results of a modeling study published in Cancer.
Black men also appeared more likely to experience progression to metastatic disease, results showed.
“Based on our findings, we feel that there is a case to be made for screening black men at earlier ages and possibly more often than other men,” Ruth Etzioni, PhD, biostatistician with the division of public health sciences at Fred Hutchinson Cancer Research Center, told HemOnc Today. “Our findings are the first step toward a comprehensive answer to this question. To determine how we should screen black men differently, we need to know how the disease differs in black men.”
Prostate cancer — the second-leading cause of cancer death among American men, behind lung cancer — is far more prevalent in black men in the United States. Incidence rates are 60% higher among black men and mortality rates are more than double that of white men.
Researchers from Fred Hutchinson Cancer Research Center, University of Michigan and Erasmus University in the Netherlands evaluated three models of prostate cancer natural history in black men and the general public. The models were formed using PSA screening data from the National Health Interview Survey in 2005 and prostate cancer incidence data from SEER for 1975 to 2000.
Across the models, the risk for developing preclinical — or asymptomatic — prostate cancer was 24% to 29% for all men, whereas the risk for black men ranged from 30% to 43% — or 28% to 56% higher than the risk of the general population.
The risk for a clinical diagnosis was 33% to 70% higher in black men than the general population.
Among those with preclinical disease onset, the risk for clinical diagnosis was comparable among black men (range, 35%-49%) as other races (range, 32%-44%), but the risk for progression to metastatic disease by the time of diagnosis was 44% to 75% higher for black men.
Overall, black men were more likely to develop prostate cancer at a younger age and to have that cancer progress to a metastatic state and/or higher grade before clinical diagnosis.
“Our study suggests that the higher incidence is probably largely attributable to black men being more likely to develop prostate cancer at any age, but we did not explore the reasons for this, whether genetic or environmental,” Etzioni said. “The higher mortality is a consequence of the higher incidence and, also, of poorer survival following diagnosis, which may be a consequence of treatment choice.”
For example, black men with localized disease undergo surgery less often than white men. Access to care and quality of care also may be factors.
“In addition, our analysis shows that in black men, prostate cancer is more likely to spread by the time they get diagnosed, although we do not attribute this to delays in being diagnosed, rather to a greater risk for disease spreading once it develops,” Etzioni said.
One limitation of the study, according to researchers, is that PSA screening rates used by all three models are based on retrospective reconstruction rather than a prospective tracking of prostate cancer screening dissemination in the U.S. population. More research is needed to assess the benefits of earlier detection and the potential harms of overdiagnosis with increased PSA screenings in black men, who Etzioni said are understudied.
“Now that we understand how underlying disease progression differs for black men, we would like to do the same assessment so we can make recommendations based on the balance of harms — including overdiagnosis — to benefits,” Etzioni said. “The problem of prostate cancer in black men cannot be addressed by screening trials in which they are underrepresented and/or a small minority. Yet, the disease is very prevalent in this population, and many black men die of prostate cancer. I hope that this paper will convince panels developing guidelines to consider making recommendations separately for this group.”
In 2016, one in six black men were diagnosed with prostate cancer, and one in 23 died of their disease, Lauren P. Wallner, PhD, MPH, faculty member and researcher in the departments of medicine and epidemiology at University of Michigan, and Steven J. Jacobsen, MD, PhD, researcher at Kaiser Permanente Southern California, wrote in a related editorial.
“A wealth of literature exists in this area and has spawned myriad studies aimed at elucidating underlying causes of these disparities, including sociodemographics; genetics; environmental factors; health behaviors; differences in tumor biology; access to care issues; and variations in screening, detection, treatment and posttreatment surveillance,” Wallner and Jacobsen wrote. “And yet there remains a lack of data on the effectiveness of prostate cancer screening in black men.”
Precision medicine and personalized health initiatives can be applied to better tailor screening practices to black men, Wallner and Jacobsen wrote.
“It may be time for the conversation around PSA screening to really focus on more personalized approaches to screening in high-risk black men,” they wrote. – by Chuck Gormley
For more information:
Ruth Etzioni, PhD, can be reached at Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 100 Fairview Ave. North, M2-B230, Seattle WA 98109-1024; email: firstname.lastname@example.org.
Disclosure: The NCI funded this study. Etzioni reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures. Wallner reports a prior grant from GlaxoSmithKline outside the scope of this study.