Proffered Presentations Archive

UK & Ireland Prostate Brachytherapy Conference 2024

Abstract number 25 

Predictive factors in US-MRI fusion prostate biopsy: a review of 2347 case.

Harry Gibbard, Dominic Hodgson, Inna O’Hea, Sarah Wilby
Portsmouth Hospitals University NHS Trust

Purpose: Identify parameters, via a retrospective review of US-MRI fusion targeted biopsies, that predict detection rates of prostate cancer (PCa), in order to rationalise our service. 

Methods: Lesions scored PI-RADS 3, for 2347 patients biopsied between 2018 and 2023, were included. Biopsy histopathology results were evaluated using descriptive statistics and ROC analysis, alongside PI-RADS score, prostate-specific antigen (PSA) & PSA density (PSAd). The impact on detection rates of the clinicians involved and the use of general or local anaesthesia, was also considered. 

Results: Cancer was detected in 1489 (63.4%) patients, of which 1124 (47.9%) had a clinically significant PCa (Gleason score >6). Cancer detection rates for PI-RADS 3, 4 and 5 lesions were 24.6% (200/813), 54.6% (962/1762) and 69.8% (609/873), respectively, and 12.2% (99/813), 38.1% (672/1762) and 56.7% (495/873) respectively for clinically significant PCa. PSA was not as effective a predictor of PCa as PSAd. Area Under Curve for PSA was 0.559 and 0.750 for PSAd. 486 patients had a maximum PI-RADS score of 3, with 606 reported lesions. 22.9% (139/606) had a positive biopsy and 12.7% (77) were clinically significant. Excluding patients with a PSAd of >0.1 ng/ml2 this detection rate reduces to 11.2% (24/214) and 6.1% (13/214) clinically significant [1]. Detection rates for patients who had a general and a local anaesthetic were 60.6% (1595) and 69.7% (745) respectively. A large range in detection rates between radiologists was identified; 16-36% (PI-RADS 3), 48-81% (PI-RADS 4) and 51-96% (PI-RADS 5). A comparatively smaller range was found when accounting for surgeons and medical physicists; 24-26% (PI-RADS 3), 54-65% (PI-RADS 4) and 77-80% (PI-RADS 5). 

Conclusion: Clinically significant PCa detection in this cohort of patients with a PI-RADS score of 3 and PSAd of less than 0.1 ng/ml2 was just 6.1%, raising questions as to whether biopsies could be avoided in this group. 

References: 

1. Washino S, Okochi T, Saito K, Konishi T, Hirai M, Kobayashi Y, et al. Combination of prostate imaging reporting and Data System (PI-RADS) score and prostate-specific antigen (PSA) density predicts biopsy outcome in prostate biopsy naïve patients. BJU International. 2016;119(2):225-233.