Race a factor in prostate cancer risk reclassification

Baltimore-African-American men with very low-risk prostate cancer being followed on active surveillance are at significantly higher risk for disease upgrading on subsequent biopsy compared to Caucasian men, according to analyses of prospectively collected data from the Johns Hopkins Active Surveillance registry.

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The study was presented at the 2014 AUA annual meeting in Orlando, FL, and more recently published in Urology (2015; 85:155-60). It included 39 African-American men and 615 Caucasian men identified as meeting all National Comprehensive Cancer Network criteria for very low-risk disease (clinical stage ≤T1, Gleason ≤6, PSA <10.0 ng/mL, PSA density <0.15 ng/mL/cc, positive cores <3, percent cancer per core ≤50%). The two racial cohorts were similar in age at entry into active surveillance and in their findings on initial biopsy.

Median follow-up duration for the African-American and Caucasian men was also similar (30.5 and 36.3 months, respectively), and there was no significant difference between the two groups in the proportion who showed progression on serial biopsy based on volume criteria (48.7% vs. 52.4%, respectively).

However, a significantly higher proportion of African-American men than Caucasians experienced upgrading on serial biopsy overall (35.9% vs. 16.1%; p<.001) and in an analysis of the cumulative incidence of upgrading (p=.002). On multivariable analysis adjusting for PSA, prostate size, volume of cancer on biopsy, and body mass index, African-American race was an independent predictor of grade reclassification, with the likelihood of this event being threefold higher in African-American men compared to Caucasians (p=.002).

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“We believe this information should be included when counseling African-American men who are considering active surveillance. If the goal of active surveillance is to select and monitor men with low-grade prostate cancer, our study findings indicate that black men may benefit from alternate enrollment criteria,” said lead author Debasish Sundi, MD, resident at Johns Hopkins’ Brady Urological Institute, Baltimore.

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He noted that the motivation for the study was derived in part from the fact that African-Americans are under-represented in outcomes studies of active surveillance cohorts and because recent evidence shows that among men with very low-risk prostate cancer who undergo immediate surgery, African-Americans are more likely than Caucasians to have adverse pathologic features.

Dr. Sundi observed that the findings of this study are consistent with analyses of active surveillance cohorts by investigators at Duke University and the University of Miami. While the Johns Hopkins study includes more African-American men than the two earlier reports, Dr. Sundi acknowledged that relatively small sample size is a limitation of the Johns Hopkins study.

“Nevertheless, because it is from a prospectively followed cohort and considering it is the largest African-American sample size studied to date, we believe it is a useful contribution to our understanding of associations between race and outcomes of active surveillance,” he told Urology Times.

While the findings beg the question of what the alternate criteria should be to select African-American men for active surveillance, the answer is unknown.

“The most important outcome is prostate cancer-specific mortality. In order to evaluate this rigorously in any cohort of men having such benign disease features overall, long-term follow-up is necessary,” said Dr. Sundi.

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Senior author Edward M. Schaeffer, MD, PhD, professor of urology at Johns Hopkins, addressed the key point of the research. He told Urology Times, “While active surveillance remains a viable option for African-American men, we need to ensure that we are not enrolling black men who either have unrecognized high-grade prostate cancer or who are at high risk for its development.”

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