Lesion volume predicts prostate cancer risk and aggressiveness: validation of its value alone and matched with prostate imaging reporting and data system score.
To demonstrate the association between magnetic resonance imaging (MRI) estimated lesion volume (LV), prostate cancer detection and tumour clinical significance, evaluating this variable alone and matched with Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) score.



We retrospectively analysed 157 consecutive patients, with at least one prior negative systematic prostatic biopsy, who underwent transperineal prostate MRI/ultrasonography fusion-targeted biopsy between January 2014 and February 2016. Suspicious lesions were delineated using a 'region of interest' and the system calculated prostate volume and LV. Patients were divided in groups considering LV (≤0.5, 0.5-1, ≥1 mL) and PI-RADS score (1-5). We considered clinically significant prostate cancer as all cancers with a Gleason score of ≥3 + 4 as suggested by PI-RADS v2. A direct comparison between MRI estimated LV (MRI LV) and histological tumour volume (HTV) was done in 23 patients who underwent radical prostatectomy during the study period. Differences between MRI LV and HTV were assessed using the paired sample t-test. MRI LV and HTV concordance was verified using a Bland-Altman plot. The chi-squared test and logistic and ordinal regression models were used to evaluate difference in frequencies.



The MRI LV and PI-RADS score were associated both with prostate cancer detection (both P < 0.001) and with significant prostate cancer detection (P < 0.001 and P = 0.008, respectively). When the two variables were matched, increasing LV increased the risk within each PI-RADS group. Prostate cancer detection was 1.4-times higher for LVs of 0.5-1 mL and 1.8-times higher for LVs of ≥1 mL; significant prostate cancer detection was 2.6-times for LVs of 0.5-1 mL and 4-times for LVs of ≥1 mL. There was a positive correlation between MRI LV and HTV (r = 0.9876, P < 0.001). Finally, Bland-Altman analysis showed that MRI LV was underestimated by 4.2% compared to HTV. Study limitations include its monocentric and retrospective design and the limited cohort.



This study demonstrates that PI-RADS score and the MRI LV, independently and in combination, are associated with prostate cancer detection and with tumour clinical significance.
Department of Urology, University of Modena and Reggio Emilia, Modena, Italy.
Eugenio
E
Martorana
Department of Urology, University of Modena and Reggio Emilia, Modena, Italy.
Giacomo Maria
GM
Pirola
Department of Surgical and Biomedical Sciences, Division of Radiology 2, Perugia University, Perugia, Italy.
Michele
M
Scialpi
Department of Urology, University of Modena and Reggio Emilia, Modena, Italy.
Salvatore
S
Micali
Department of Urology, University of Modena and Reggio Emilia, Modena, Italy.
Andrea
A
Iseppi
Department of Diagnostic Medicine and Public Health -Section of Pathology, University of Modena and Reggio Emilia, Modena, Italy.
Luca Reggiani
LR
Bonetti
Department of Medical Statistic, University of Modena and Reggio Emilia, Modena, Italy.
Shaniko
S
Kaleci
Department of Diagnostic Imaging, University of Modena and Reggio Emilia, Modena, Italy.
Pietro
P
Torricelli
Department of Urology, University of Modena and Reggio Emilia, Modena, Italy.
Giampaolo
G
Bianchi
D000368:Aged; D006801:Humans; D061705:Image-Guided Biopsy; D007558:Italy; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009929:Organ Size; D011237:Predictive Value of Tests; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000473:pathology*; D012189:Retrospective Studies; D047368:Tumor Burden
D017430:Prostate-Specific Antigen
PI-RADS v2 score; clinically significant prostate cancer; lesion volume; prostate cancer detection; tumour aggressiveness