Improving risk stratification in a community-based African American population using cell cycle progression score

Walter Rayford, Mark Greenberger, Randy V. Bradley


Background: Current clinical nomograms such as American Urological Association/National Comprehensive Cancer Network (AUA/NCCN) risk categories or CAPRA may not always reflect prostate cancer (PCa) risk among African American men. We evaluated the usefulness of adding a commercially available cell cycle progression (CCP) score to improve risk stratification in a community-based African American population.
Methods: Biopsy tissues from 150 African American and 60 Caucasian men were obtained from a single community urologic oncology practice in Memphis, TN. The biopsy samples were evaluated with a commercially available CCP panel (Prolaris). Clinical variables such as Gleason score, prostate-specific antigen (PSA), age, clinical stage, and extent of disease were combined to determine a single category of low-, intermediate-, or high-risk. AUA risk stratification for cancer aggressiveness was then compared between the CCP score vs. the clinical parameters to determine potential risk improvement by the CCP score.
Results: Based on the clinical parameters, of the 150 African American men evaluated, 20% were classified as low-risk, 40% were classified as intermediate-risk, and 40% were classified as high-risk. Of the 60 Caucasian men evaluated, 42% were low-risk, 42% were intermediate-risk, and 17% were high-risk. However, when re-evaluating the African American patients using the CCP score, 30% of the patients were determined to be more aggressive than the clinical low-risk category. Similarly, 21.67% of the patients were found to be more aggressive than the clinical intermediate-risk category, and 23.33% of the patients were more aggressive than the high-risk category. When compared to our Caucasian cohort, 12% of the low-risk patients, 8% of the intermediate-risk patients, and 10% of the high-risk patients were found to be more aggressive by the CCP score. Overall, 24% of African American men vs. 10% of Caucasian men were reclassified to a higher risk by CCP score. When we compared the mean CCP score in the African American population vs. the Caucasian population, the mean CCP score in the AUA low-risk was 3.2 vs. 2.9; 3.4 vs. 3.2 in the AUA intermediate-risk; and 3.8 vs. 3.5 in the AUA high-risk category, respectively. Despite the higher mean CCP score in the African American population, the difference between the African American men and the Caucasian men was not significant (P=0.064 for low-risk, P=0.204 for intermediate-risk, and P=0.209 for high-risk).
Conclusions: Our data extends the evidence that CCP score derived from a biopsy specimen can be clinically useful. Our findings showed that the CCP score could stratify 10-year mortality risk in African American men beyond the current clinicopathologic features, which may better prepare patients for follow-up visits and discussions with their health care provider(s) and enhance their ability to select the most appropriate treatment option.