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

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.

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.

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).

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.