Abstract 2301: Indications for systematic prostate biopsy in men with negative multi-parametric magnetic resonance imaging

Abstract

Abstract Introduction: Multiparametric Magnetic Resonance Imaging (mpMRI) is a valuable tool in the prostate cancer diagnostic pathway, and MRI-influenced biopsy has been shown to be superior to systematic biopsy alone for detecting clinically significant prostate cancer (csPCa), defined as the presence of any Gleason ≥ 4. Negative predictive value of mpMRI for csPCa varies widely in published reports, with a median of approximately 88%. Counselling patients with negative mpMRI (PIRADS score <3)to decide whether or not to proceed with systematic biopsy or PSA monitoring could be challenging. Several studies have shown that a PSA density (PSAD) ≥ 0.15 is an indication for systematic biopsy. We analysed the clinical, radiological and pathological features of patients with negative mpMRI but csPca on systematic biopsy to identify other criteria that may inform the need for systematic biopsy when mpMRI is negative. Methods: For 18 months between Nov 2017 and May 2019, all men on our prostate diagnostic pathway with negative mpMRI were offered systematic biopsy. The criteria for pre-biopsy mpMRI was any man suitable for radical surgery or radiotherapy, plus one or more of PSA ≥ 3, palpable lesion on digital rectal examination, or family history of PCa in a first degree relative (father or brother). mpMRI was performed with a 1.5-Tesla magnet and included T2, DWI and DCE sequences. Systematic biopsy was TRUS-guided, with 8-16 biopsy cores. Results: Of 589 mpMRI scans in 573 men, 216 (37%) had negative mpMRI. Of these, 141 (65%) proceeded with systematic biopsy. Among the men that had biopsy, Gleason 3+3 was detected in 12 men (9%) and Gleason ≥ 4 in six (4%). Important pre-biopsy features in men with Gleason ≥ 4 were PSAD ≥ 0.15 (n=3), artefact on MRI from hip joint prosthesis (n=1), and family history (n=2). There were no unusual histological variants seen on the positive biopsy cores. Conclusion: Most men with negative mpMRI can avoid prostate biopsy and be managed with PSA monitoring. Based on our experience, we recommend systematic biopsy in men with negative mpMRI who have PSAD ≥ 1.5, family history or any imaging artifact that may alter image interpretation. Citation Format: Chidi N. Molokwu, Christos Gkikas, Harry Bardgett, Nicola Lee, Faisal Ali, Rohit Chahal, Rajindra Singh. Indications for systematic prostate biopsy in men with negative multi-parametric magnetic resonance imaging [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2301.