Diagnostic evaluation and incorporation of PSA density and the prostate imaging and data reporting system (PIRADS) version 2 classification in risk-nomograms for prostate cancer.

ABSTRACT

PURPOSE: The diagnostic approach for prostate cancer still depends on PSA and DRE. OBJECTIVES: to evaluate the diagnostic validity of PSA-Density and PIRADSv2 as diagnostic tests regarding biopsy results, and to design nomograms that include all diagnostic variables for malignancy, significant tumor (ST) and high-grade tumor. METHODS: Cross-sectional study which included men with PSA ≥ 4 ng/ml and/or suspicious DRE, PIRADSv2 ≥ 3 lesions on multiparametric MRI and prostate biopsy. The gold standard test was the maximum ISUP of the targeted biopsy per patient (malignancy ISUP ≥ 1, ST ISUP ≥ 2, high-grade tumor ISUP ≥ 4). Association and logistic regression tests were used and diagnostic validity parameters using PSA-Density and PIRADSv2 classification was analyzed. Nomograms were designed for malignancy, ST, and high-grade tumor using the best model selection procedure from all possible equations. RESULTS: 336 men with median age, PSA and PSA-Density of 67.7 years (IQR12.6), 6.3 ng/ml (IQR3.3) and 0.12 ng/ml/cc (IQR0.10), respectively; 63 index lesions were PIRADS3, 204 PIRADS4, and 69 PIRADS5. 65.8% and 37.8% were malignant and ST, respectively. The significant positive association highlighted between malignancy and ST with age, DRE, PSA-Density and PIRADSv2. PSA-Density and PIRADSv2 ≥ 3 presented the highest sensitivity to detect malignancy, and their combination showed sensitivity nearly 95% (AUC0.803). Nomograms for malignancy and ST included the variables age, DRE, PSA-Density, and PIRADSv2 with a sensitivity closely 91% (AUC0.833), and a specificity of almost 85% for ST, exposing risk < 5% for ST when PSA-Density is < 0.15, not suspicious DRE and PIRADS3. CONCLUSION: PSA-Density and PIRADSv2 classification in risk nomograms can provide highly relevant information to increase the accuracy in the diagnosis of PC and ST.