Are Big Prostates a Challenge? Correlation Between Prostate Volume and Detection Rate in Fusion Biopsy of the Prostate

Background This study investigates the relationship between prostate cancer (PCa) detection rates and prostate volume. Prostate volume may influence the diagnostic performance of MRI–ultrasound (MRI–US) fusion biopsy. Enlarged prostate glands present specific challenges, including reduced specificity of prostate‐specific antigen (PSA), anatomical alterations of the transition zone, and potential limitations in biopsy accuracy. Material and Methods We retrospectively analyzed 1300 consecutive patients with elevated PSA and/or abnormal digital rectal examination (DRE) who underwent MRI–US fusion‐guided biopsy between 2014 and 2023. Patients were stratified into five prostate volume groups (< 30, 30–54.9, 55–79.9, 80–119.9, and ≥ 120 mL). For PI‐RADS–based analyses, three volume categories (< 50, 50–100, and > 100 mL) were applied. Detection rates for overall PCa and clinically significant prostate cancer (csPCa) were assessed. Results A total of 1203 patients were included. The overall cancer detection rate was 62.0% (746/1203), with 39.5% (475/1203) classified as clinically significant. Detection rates decreased significantly with increasing prostate volume, from 82.3% in prostates < 30 mL to 28.9% in prostates ≥ 120 mL ( p < 0.01). Intermediate groups showed detection rates of 67.1%, 50.2%, and 48.5% for volumes of 30–54.9, 55–79.9, and 80–119.9 mL, respectively. A similar trend was observed for csPCa detection (59.4%, 42.3%, 27.4%, 31.5%, and 24.4%; p < 0.05). In multivariable analysis, prostate volume remained an independent predictor of cancer detection (OR: 0.99, p < 0.01). Stratified by PI‐RADS category, detection rates consistently declined with increasing prostate size. For PI‐RADS 5 lesions, detection decreased from 87.1% in prostates < 50 mL to 83.1% in 50–100 mL and 69.2% in > 100 mL ( p < 0.01). Comparable trends were observed for PI‐RADS 4 lesions (78.5%, 64.0%, and 50.0%) and PI‐RADS 3 lesions (45.9%, 40.7%, and 31.8%; p < 0.05). Additionally, larger prostates were associated with a higher proportion of anterior lesions and a decreasing rate of positive DREs. Conclusion Prostate volume is an independent determinant of cancer detection in MRI–US fusion biopsy. Larger prostate glands are associated with significantly reduced detection rates across all PI‐RADS categories. These findings highlight the need to consider prostate volume in diagnostic decision‐making and to adapt biopsy strategies in patients with enlarged prostates.