Stratification of the aggressiveness of prostate cancer using pre-biopsy multiparametric MRI (mpMRI)

• Published in: NMR in biomedicine Vol. 29; no. 3; pp. 232 - 238
• Main Authors: Dwivedi, Durgesh Kumar, Kumar, Rajeev, Bora, Girdhar S., Thulkar, Sanjay, Sharma, Sanjay, Gupta, Siddhartha Datta, Jagannathan, Naranamangalam R.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.03.2016; Wiley Subscription Services, Inc
• Subjects: Aged; Biopsy; Diffusion; diffusion-weighted MRI (DWI); disease aggressiveness; Humans; Magnetic Resonance Imaging - methods; Male; Metabolome; MR spectroscopic imaging (MRSI); multiparametric MRI (mpMRI); Neoplasm Grading; Neoplasm Invasiveness - diagnostic imaging; Prostate cancer; Prostatic Neoplasms - diagnostic imaging; Prostatic Neoplasms - pathology; ROC Curve; stratification; stratification, multiparametric MRI (mpMRI); prostate cancer; MR spectroscopic imaging (MRSI); diffusion-weighted MRI (DWI); disease aggressiveness; stratification, multiparametric MRI (mpMRI)
• ISSN: 0952-3480; 1099-1492
• DOI: 10.1002/nbm.3452

Risk stratification, based on the Gleason score (GS) of a prostate biopsy, is an important decision‐making tool in prostate cancer management. As low‐grade disease may not need active intervention, the ability to identify aggressive cancers on imaging could limit the need for prostate biopsies. We assessed the ability of multiparametric MRI (mpMRI) in pre‐biopsy risk stratification of men with prostate cancer. One hundred and twenty men suspected to have prostate cancer underwent mpMRI (diffusion MRI and MR spectroscopic imaging) prior to biopsy. Twenty‐six had cancer and were stratified into three groups based on GS: low grade (GS ≤ 6), intermediate grade (GS = 7) and high grade (GS ≥ 8). A total of 910 regions of interest (ROIs) from the peripheral zone (PZ, range 25–45) were analyzed from these 26 patients. The metabolite ratio [citrate/(choline + creatine)] and apparent diffusion coefficient (ADC) of voxels were calculated for the PZ regions corresponding to the biopsy cores and compared with histology. The median metabolite ratios for low‐grade, intermediate‐grade and high‐grade cancer were 0.29 (range: 0.16, 0.61), 0.17 (range: 0.13, 0.32) and 0.13 (range: 0.05, 0.23), respectively (p = 0.004). The corresponding mean ADCs (×10–3 mm2/s) for low‐grade, intermediate‐grade and high‐grade cancer were 0.99 ± 0.08, 0.86 ± 0.11 and 0.69 ± 0.12, respectively (p < 0.0001). The combined ADC and metabolite ratio model showed strong discriminatory ability to differentiate subjects with GS ≤ 6 from subjects with GS ≥ 7 with an area under the curve of 94%. These data indicate that pre‐biopsy mpMRI may stratify PCa aggressiveness noninvasively. As the recent literature data suggest that men with GS ≤ 6 cancer may not need radical therapy, our data may help limit the need for biopsy and allow informed decision making for clinical intervention. Copyright © 2015 John Wiley & Sons, Ltd. The stratification of patients with prostate cancer (PCa) is of prime importance for appropriate treatment. We present the ability of pre‐biopsy multiparametric MRI (mpMRI) to stratify the tumor aggressiveness of PCa. Pre‐biopsy MRSI and diffusion‐weighted imaging (DWI) correlated with the Gleason score (GS) of PCa on transrectal ultrasound (TRUS) biopsy. Using mpMRI, we were able to stratify PCa aggressiveness, which may help to plan the management of patients with PCa and to choose appropriate therapy.