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The performance of the 4Kscore for predicting high-grade prostate cancer does not depend on patient age
Introduction: The 4Kscore is a blood test combining four kallikrein assays with clinical information in an algorithm. A multisite US prospective study demonstrated that the 4Kscore accurately predicted the probability of high-grade cancer on prostate biopsy (PNBx). The 4Kscore performance was investigated by patient age group for accuracy in predicting risk for aggressive prostate cancer.
Methods: The study enrolled 1012 men referred for PNBx. The 4Kscore prediction of high-grade cancer was calculated without knowledge of the histopathology. Differential calibration by age was assessed using logistic regression modeling and interaction between age and the 4Kscore for the outcome of high-grade prostate cancer.
Results: Among the 1012 men in the validation cohort, 231 (23%) were found to have high-grade cancer on prostate biopsy. The median age was 66 (IQR 61, 72), which was significantly different than those without prostate cancer [63 (57, 68)] and those with low-grade cancer [64 (IQR 59, 69)] (P<0.0001). There was no significant interaction between age and the 4Kscore in predicting high-grade prostate cancer (p=0.5). The confidence intervals for the difference in AUC between each age subgroup included zero indicating the AUCs for the various subgroups were not significantly different from one another.
Conclusion: The 4Kscore accurately predicted the presence of high-grade prostate cancer in a prospective study. There was no significant difference in the performance of the 4Kscore Test for patients of various age groups in determining the need for PNBx.