Role of systematic biopsies in suspected prostate carcinoma patients and analysis of Gleason grade group concordance between the biopsy and histopathology report following radical prostatectomy.

Abstract

e17126 Background: In biopsy-naïve patients with suspicious lesions on MRI, magnetic resonance (MR) targeted biopsy of the lesion and systematic biopsy are currently considered the standard of care. However, this mandate has never been adequately studied in the Indian population. With this study, we aimed to compare the ability of MR-targeted versus systematic biopsies to detect overall as well as clinically significant prostate cancer (csPC) and analyze Gleason grade group concordance between these biopsies with the final histopathology report (HPE) following Robot-assisted radical prostatectomy (RARP). Methods: We retrospectively analyzed data of patients suspected of PC (raised PSA or abnormal DRE) who underwent MR-transrectal ultrasonogram (TRUS) fusion-guided biopsies of the prostate and RARP at our center from December 2017 to July 2024. All of the patients first underwent mpMRI of the prostate followed by MR-TRUS fusion biopsy of the prostate (PIRADS ≥3). csPC was defined as the presence of PC ISUP grade ≥2. The study's primary objective was to compare the diagnostic accuracy of targeted and systematic biopsies for csPC. Additionally, we determined Gleason grade group discrepancies between the biopsies with the final HPE following RARP as a reference standard. Results: Of the 597 patients who underwent fusion biopsy, 342 (57.3%) were found to be positive for PC. Of these 342 patients, 256 (74.9%) had csPC and eventually, 132 (51.6%) patients underwent RARP. The systematic biopsy had a sensitivity, specificity and PPV of 95.7%, 72.9% and 93.1% respectively whereas, the targeted biopsy had a sensitivity, specificity and PPV of 93.1%, 81.4% and 95.7% respectively to detect csPC. Performing only targeted biopsies would miss 91/342 (26.6%) csPC lesions and detect 19/342 (5.6%) additional tumours. The highest Gleason score of systematic biopsies when compared with the final HPE post-RARP, showed upgradation of 88%, 25.5%, 12%, 9.1% of Gleason scores 3+3, 3+4, 4+3 and 4+4 respectively and a down-gradation of 9.1%, 36%, 54.6%, 100%, 100% of Gleason scores 3+4, 4+3, 4+4, 5+4, 5+5 respectively. The highest Gleason score of targeted biopsies when compared with the final HPE post-RARP, showed upgradation of 100%, 37.9%, 13.6%, 50% of Gleason scores 3+3, 3+4, 4+3 and 4+4 respectively and a down-gradation of 5.2%, 31.8%, 25%, 50% of Gleason scores 3+4, 4+3, 4+4, 4+5 respectively. Conclusions: Targeted biopsy has superior specificity and PPV compared to systematic biopsy. The higher Gleason grade groups in targeted biopsies have more concordance with final HPE compared to TRUS biopsy. However, performing only targeted biopsies would lead to under-detection of csPC lesions with lower concordance with the final HPE in lower Gleason grade group patients.