Racial Variation in the Utility of Urinary Biomarkers PCA3 and T2ERG in a Large Multicenter Study

Abstract

To our knowledge it is unknown whether urinary biomarkers for prostate cancer have added utility to clinical risk calculators in different racial groups. We examined the utility of urinary biomarkers added to clinical risk calculators for predicting prostate cancer in African American and nonAfrican American men. Demographics, PCPT (Prostate Cancer Prevention Trial) risk scores, data on the biomarkers data PCA3 (prostate cancer antigen 3) and T2ERG (transmembrane protease serine 2 and v-ets erythroblastosis virus E26 oncogene homolog gene fusion), and biopsy pathology features were prospectively collected on 718 men as part of EDRN (Early Detection Research Network). Utility was determined by generating ROC curves and comparing AUC values for the baseline multivariable PCPT model and for models containing biomarker scores. PCA3 and T2ERG added utility for the prediction of prostate cancer and clinically significant prostate cancer when combined with the PCPT Risk Calculator. This utility was seen in nonAfrican American men only for PCA3 (AUC 0.64 increased to 0.75 for prostate cancer and to 0.69-0.77 for clinically significant prostate cancer, both p <0.001) and for T2ERG (AUC 0.64-0.74 for prostate cancer, p <0.001, and 0.69-0.73 for clinically significant prostate cancer, p = 0.029). African American men did not have an added benefit with the addition ofbiomarkers, including PCA3 (AUC 0.75-0.77, p = 0.64, and 0.65-0.66, p=0.74)and T2ERG (AUC 0.75-0.74, p = 0.74, and 0.65-0.64, p = 0.88), forprostate cancer and clinically significant prostate cancer, respectively. Limitations include the small number of African American men (72). The post hoc subgroup analysis nature of the study limited findings to being hypothesis generating. As novel biomarkers are discovered, clinical utility should be established across demographically diverse cohorts.