title: Stratification of the aggressiveness of prostate cancer using pre-biopsy multiparametric MRI (mpMRI).
abstract: 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) mm(2) /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.
authors.affiliation: Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Durgesh Kumar
authors.initials: DK
authors.lastname: Dwivedi
authors.affiliation: Department of Urology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Urology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Girdhar S
authors.initials: GS
authors.lastname: Bora
authors.affiliation: Department of Radio-diagnosis, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Thulkar
authors.affiliation: Department of Radio-diagnosis, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Siddhartha Datta
authors.initials: SD
authors.lastname: Gupta
authors.affiliation: Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Naranamangalam R
authors.initials: NR
authors.lastname: Jagannathan
mesh_terms: D000368:Aged; D001706:Biopsy; D004058:Diffusion; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055442:Metabolome; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D012372:ROC Curve
keywords: MR spectroscopic imaging (MRSI); diffusion-weighted MRI (DWI); disease aggressiveness; prostate cancer; stratification, multiparametric MRI (mpMRI)