The feasibility of distance to the tumor of biopsy cores to estimate the extracapsular extension.

Background: To investigate the predictive capability of a new parameter, the distance between the fibromuscular capsule and the tumor as measured using a prostate biopsy core (referred to as "distance to the tumor" [DTT]), for the presence of extracapsular extension (ECE).

Materials And Methods: We analyzed specimens obtained from 246 patients diagnosed with prostate cancer. All patients underwent prebiopsy, prostate magnetic resonance imaging (MRI), and subsequent prostatectomy. DTT measurements were obtained for each prostate biopsy core, and the minimum (min) DTT was extracted. We assessed the relationship between min DTT, MRI-estimated ECE, and pathological ECE, considering factors such as the PI-RADS score and tumor location.

Results: In this study of 246 patients, the mean age was 65.8 years, and the mean prostate-specific antigen (PSA) level was 18.9 ng/ml. Patients with suspicious lesions in the peripheral zone and pathological ECE displayed higher rates of positive digital rectal examination (DRE), elevated PSA levels, and shorter DTT values in the biopsy cores. DTT demonstrated an accurate estimation of the presence of ECE, similar to MRI findings. Min DTT exhibited higher accuracy for peripheral zone masses, with a cutoff value of 1.0 mm for min DTT predicting ECE (AUC: 0.84, sensitivity: 72.23%, specificity: 77.78%,  < 0.01). Of the 246 patients, 66 had no ECE on MRI; however, 18 of these patients displayed pathological ECE, with 14 having DTT values <1.0 mm.

Conclusions: Min DTT, positive DRE results, and a higher Gleason grade were significantly associated with ECE. DTT measurements of <1 mm can provide a more accurate prediction of ECE in the peripheral zone of the prostate than MRI-based assessments.