Published in:
01-04-2016 | Urology - Original Paper
Validating multiparametric MRI for diagnosis and monitoring of prostate cancer in patients for active surveillance
Published in: International Urology and Nephrology | Issue 4/2016
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Purpose
To compare multiparametric magnetic resonance imaging (mpMRI) with transrectal ultrasound-guided prostate biopsy (TRUS-bx) for the diagnosis and monitoring of small-volume prostate cancer (PCa) in patients on active surveillance (AS).
Methods
In a retrospective cross-sectional validation study, 100 patients on AS for PCa underwent a systematic 12-core TRUS-bx (the gold standard) as well as mpMRI, on either a 1.5 or 3 Tesla scanner (32 and 68 patients, respectively). Three pathologists reported biopsy histology separately. A single, experienced radiologist scored mpMRI scans using the PI-RADS system. We compared left- and right-sided PI-RADS scores of the peripheral zone with TRUS-bx results of the relevant prostate lobe. We then estimated the specificity and sensitivity of mpMRI in diagnosing low-grade low-risk PCa in our AS cohort.
Results
The sensitivity of mpMRI was 37 % (95 % CI 28–47 %) and specificity was 85 % (CI 76–92 %) for cancer. The negative predictive value was 51 % (CI 44–60 %), and the positive predictive value was 76 % (CI 62–87 %). The positive and negative likelihood ratios were 2.5 and 0.7, respectively.
Conclusion
Because of its low specificity and low negative predictive value, mpMRI is not suitable for diagnosing low-grade small-volume PCa. However, because of a specificity of 85 % and a negative likelihood ratio of 0.7, mpMRI may be useful for follow-up of previously TRUS-bx diagnosed patients who are on AS.