Mark A. Preston, MD, MPH
In a study published by Mark A. Preston, MD, MPH, and colleagues in European Urology, researchers demonstrated that a baseline prostate-specific antigen (PSA) level obtained from black men between 40 and 60 years old may predict the future development of prostate cancer for years after testing.
The study builds on earlier work in the United States and Sweden, which demonstrated a strong link between elevated midlife PSA levels and later development of prostate cancer among primarily white men. Given the pronounced racial disparities in prostate cancer, research on screening in African American men has become a U.S. Preventive Services Task Force priority.
The investigators for this study utilized data and blood samples from participants in the Southern Community Cohort Study (SCCS), a prospective cohort of 86,000 men and women recruited through community health centers in 12 southern states. Established by the National Cancer Institute in 2001 to address health disparities, the SCCS has the highest representation of African Americans among existing cohorts, as well as a large biorepository.
Researchers selected black men within the SCCS cohort who were aged 40 to 64 at the time of enrollment during 2002–2009. At time of entry into the SCCS, they were free of cancer diagnosis. Linkage with state cancer registries allowed the researchers to identify 197 within this group who had developed prostate cancer by 2015, 91 of whom had aggressive disease (advanced stage, high grade, or death attributed to prostate cancer). For each of these cases, the researchers identified up to three controls from the SCCS who matched in terms of age, study site, and date of blood draw and who survived without prostate cancer at the time of the matched case’s diagnosis. PSA levels in blood samples from the SCCS biorepository for the total of 766 cases and controls were analyzed in blinded case-control sets.
PSA Levels
The results showed that the risk of prostate cancer rose along with rising PSA levels, regardless of age. Compared to men with PSAs at or below their age-specific median, an elevated PSA baseline increased prostate cancer risk by 25% for men aged 40 to 54 and by 17.5% for men aged 55 to 64. Additionally, for men aged 40 to 54, PSA levels within the “normal” range that would not trigger a follow-up in usual clinical practice (1.1–1.7 ng/mL) still saw an increased risk for prostate cancer.
The link between aggressive prostate cancer and elevated baseline PSA was especially strong. All 36 cases of aggressive prostate cancer in men aged 40 to 54 occurred among those with baseline PSA above their age-specific median. For those aged 55 to 64, 95% (52 of 55) of aggressive prostate cancer cases were in men with elevated PSA baselines.
“Midlife PSA predicts subsequent development of aggressive prostate cancer better than either family history or race,” said co–first author and Moffitt Cancer Center epidemiologist Travis Gerke, ScD. “While these findings do not imply that these younger men should immediately undergo prostate biopsy or definitive treatment, they suggest that this group would benefit from more intensive PSA screening for earlier identification of cancer while it is potentially curable. This ‘smarter screening’ approach may allow us to identify and follow men at higher risk while reducing the population-wide harms of screening low-risk men.” ■
Preston MA, et al: Eur Urol. September 17, 2018 (early release online).
