Do African Americans with low-risk prostate cancer have lower PSA density than comparable Caucasians?


There have been a number of suggestions (as yet unproven) that African American men (and perhaps other men of black African ethnicity) may be less good candidates for active surveillance than men of Caucasian and Hispanic ethnicity. Clearly, if these suggestions are correct, this has implications for which men of black African ethnic origin, if diagnosed with low-risk prostate cancer, should consider active surveillance as a first-line management strategy.

A new paper by Kryvenko et al., in the September issue of the Journal of Urology, has now suggested that, on average, African American men with Gleason scores of 3 + 3 = 6 and other criteria classifying them as having low-risk prostate cancer may, in fact, tend to have lower PSA density levels than otherwise comparable Caucasian men.

The authors set out to investigate whether there was any difference in the levels of PSA production between African American (AA) and Caucasian men with prostate cancer that had a Gleason score 3 + 3 = 6. To do this, they measured or calculated a variety of key data among a cohort of > 400 men who underwent radical prostatectomies for low-risk prostate cancer according to the criteria of the National Comprehensive Cancer Network, including:

  • Age
  • Body mass index (BMI)
  • Tumor volume (based on post-surgical pathology)
  • PSA level at diagnosis
  • PSA density
  • PSA mass (which is an estimate of the absolute amount of PSA in the patient’s circulation)

They report that:

  • The patient cohort included 414 patients
    • 348 were of Caucasian ethnic origin
    • 66 were African Americans
  • There were no apparent or statistically significant differences between the two groups of patients with respect to
    • Age
    • BMI
    • PSA level at diagnosis
    • Dominant tumor volume
    • Total tumor volume
    • PSA mass
  • By contrast, however, compared to the Caucasians, the African American patients had
    • Heavier prostates (mean mass 55.4 g vs. 46.3 g; p ≤ 0.03)
    • Lower PSA density levels (mean PSA density 0.09 vs. 0.105; p ≤ 0.02)

Kryvenko et al. conclude that:

  • African American men with low-risk prostate cancer and Gleason scores of 3 + 3 = 6 “produce less PSA than Caucasians.”
  • African American and Caucasian men with low-risk prostate cancer and Gleason scores of 3 + 3 = 6 have “equal” PSA levels and PSA mass levels, even though the African Americans have significantly larger prostates (by mass).
  • These findings have “practical implications in T1c patients” diagnosed with prostate cancer as a consequence of PSA testing.

They also suggest that it may be advisable to use a lower PSA density criterion for African American patients (compared to Caucasian patients) in determining whether individual patients are appropriate candidates for active surveillance. (In this context, it should be noted that a PSA density level of ≤ 0.15 or 15 percent is normally used today as the ideal PSA density level for good candidates for active surveillance.)

The “New” Prostate Cancer InfoLink would suggest that, at present, this represents an interesting hypothesis that needs additional data before we start to try to apply this in clinical practice. It is based on a relatively small number of African American patients, all diagnosed at a single institution. It would be helpful to see if other institutions could replicate these data.

The complete text of this paper is currently under embargo until full editorial review has been completed. Having said that, there is no suggestion in the paper’s abstract of what type of lower PSA density level the authors might consider appropriate in the evaluation of African American men with low-risk disease as good candidates for initial management on active surveillance.

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