Utility of tumor diameter-to-prostate volume ratio for predicting the outcome of magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy.

[OBJECTIVES] To assess the impact of the tumor diameter-to-prostate volume ratio (TD/PV) on predicting prostate cancer (PCa) and clinically significant (cs) -PCa in magnetic resonance imaging (MRI) /transrectal ultrasound (TRUS) fusion-targeted biopsy based on prostate imaging-reporting and data system (PI-RADS) findings in MRI.

[MATERIALS AND METHODS] Patients who underwent MRI/TRUS fusion-targeted biopsy for PI-RADS version 2.1 categories 3-5 lesions between 2017 and 2023 were retrospectively reviewed. TD/PV was calculated by dividing the tumor diameter by the total prostate volume. csPCa was defined as a Gleason score of ≥ 3 + 4. Univariable and multivariable logistic regression analyses were used to develop predictive nomograms for PCa and csPCa. A receiver operating characteristic curve was constructed to evaluate the predictive ability of the factors using the area under the curve (AUC).

[RESULTS] A total of 565 patients were analyzed; the AUC of TD/PV was significantly superior to those of the prostate-specific antigen (PSA), tumor diameter, PSA density, and PI-RADS for predicting PCa (AUC: 0.840, P < 0.05) and csPCa (AUC: 0.819, P < 0.05). Multivariable analyses showed that TD/PV is a significant predictive factor for PCa and csPCa in MRI/TRUS fusion-targeted biopsy (P < 0.05). The predictive nomograms combining TD/PV and PI-RADS category were constructed and their AUCs for predicting PCa and csPCa were 0.861 and 0.845, respectively.

[CONCLUSIONS] In this retrospective analysis, prediction of PCa and csPCa on MRI/TRUS fusion-targeted biopsy was improved when TD/PV was combined with PI-RADS category.