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 analyse Gleason grade group concordance between these biopsies with the final histopathology report (HPE) following Robot-assisted radical prostatectomy (RARP).

We retrospectively analysed 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 centre from December 2017 to July 2024. All 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.

Among 597 patients who underwent fusion biopsy, 342 (57.3%) were positive for PC. Of these 342 patients, 256 (74.9%) had csPC and 132 (51.6%) underwent RARP. The sensitivity, specificity and PPV of the systematic biopsy were 95.7%, 72.9% and 93.1% respectively whereas, that of the targeted biopsy were 93.1%, 81.4% and 95.7% respectively. 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. Similarly, the highest Gleason score of targeted biopsies 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.

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.