Adding systematic cores to MRI-targeted biopsy in men with suspicious prostate cancer (PCa) might improve the detection of clinically significant disease. Nonetheless, the implications of adding systematic cores in predicting adverse pathologic outcomes in patients undergoing radical prostatectomy (RP) are still unknown.
Overall, 659 patients who underwent MRI-targeted biopsy and subsequent RP between 2016 and 2018 at five referral centers were identified. All patients received concomitant systematic biopsy at the time of targeted biopsy. Biopsy and prostatectomy specimens were reviewed by dedicated uro-pathologists. The D’Amico risk groups and the rate of upgrading at final pathology were assessed considering the grade group at targeted biopsy and after adding information from systematic biopsy. A multivariable logistic regression model assessing the impact of MRI-targeted biopsy parameters (PSA, prostate volume, grade group at target biopsy, clinical stage and the maximum diameter of the lesion at mpMRI) on the risk of upgrading was developed. A second model that included also information on clinically significant PCa outside the index lesion, the number of random positive and total cores was developed. The discrimination of these two models was compared using the ROC-derived area under the curve (AUC).
Median PSA was 7.8ng/ml. Biopsy grade group at target biopsy was 1, 2, 3, and ≥4 in 86 (13%), 325 (49.3%), 138 (20.9%) and 110 (17%) patients. When considering also systematic cores, biopsy grade group was 1, 2, 3, and ≥4 in 60 (9%), 333 (50%), 145 (22%) and 121 (18%) men. Overall, 86 (13.1%), 445 (67%) and 128 (19%) patients had low-, intermediate- and high-risk disease at MRI-targeted biopsy. When information obtained by systematic biopsy were added, 42 (6.4%), 451 (68%) and 166 (25%) men were classified as low-, intermediate- and high-risk. While 40 (46%) low-risk patients were reclassified as intermediate-risk, 5 (5.8%) and 33 (7.4%) low- and intermediate-risk patients were reclassified as high-risk. The rate of upgrading decreased from 32% for targeted biopsies to 28% when adding information from systematic biopsy (P=0.04). The presence of significant disease at systematic biopsy and a higher number of systematic cores taken were associated with a reduced risk of upgrading (all P≤0.01). The discrimination of a model predicting upgrading including also systematic biopsy information was higher compared to those including targeted biopsy only (AUC: 78 vs. 72%).
Adding systematic biopsy to MRI-targeted cores reduces the risk of upgrading at final pathology. Our data reinforce the need for accurate systematic biopsy sampling to improve accuracy for tumor grading and to optimize patient selection for different approaches such as active surveillance or focal therapies.