The role of magnetic resonance imaging in delineating clinically significant prostate cancer.
OBJECTIVE
To determine whether multiparametric magnetic resonance imaging might improve the identification of patients with higher risk disease at diagnosis and thereby reduce the incidence of undergrading or understaging.


METHODS
We retrospectively reviewed the clinical records of 115 patients who underwent multiparametric magnetic resonance imaging before radical prostatectomy. We used Epstein's criteria of insignificant disease with and without a magnetic resonance imaging (MRI) parameter (apparent diffusion coefficient) to calculate sensitivity, specificity, as well as negative and positive predictive values [NPV and PPV] across varying definitions of clinically significant cancer based on Gleason grade and tumor volume (0.2 mL, 0.5 mL, and 1.3 mL) on whole-mount prostate specimens. Logistic regression analysis was performed to determine the incremental benefit of MRI in delineating significant cancer.


RESULTS
The majority had a prostate-specific antigen from 4.1-10.0 (67%), normal rectal examinations (90%), biopsy Gleason score ≤ 6 (68%), and ≤ 2 cores positive (55%). Of the 58 patients pathologically staged with Gleason 7 or pT3 disease at prostatectomy, Epstein's criteria alone missed 12 patients (sensitivity of 79% and NPV of 68%). Addition of apparent diffusion coefficient improved the sensitivity and NPV for predicting significant disease at prostatectomy to 93% and 84%, respectively. MRI improved detection of large Gleason 6 (≥ 1.3 mL, P = .006) or Gleason ≥ 7 lesions of any size (P <.001).


CONCLUSIONS
Integration of MRI with existing clinical staging criteria helps identify patients with significant cancer. Clinicians should consider utilizing MRI in the decision-making process.
Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, CA. Electronic address: kchamie@mednet.ucla.edu.
Karim
K
Chamie
Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Geoffrey A
GA
Sonn
Department of Urology, Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA.
David S
DS
Finley
Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Nelly
N
Tan
Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Daniel J A
DJ
Margolis
Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Steven S
SS
Raman
Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA; Center for Advanced Surgical and Interventional Technology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Shyam
S
Natarajan
Department of Pathology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Jiaoti
J
Huang
Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Robert E
RE
Reiter
D000368:Aged; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011300:Preoperative Care; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D018570:Risk Assessment