Objective: The aim of this study was to evaluate prospectively whether diffusion-weighted magnetic resonance imaging (DW-MRI), interpreted in a routine clinical setting, can serve as a diagnostic and prognostic tool for prostate carcinoma patients on active surveillance (AS).
Material and Methods: Eighty men enrolled in the Finnish arm of the PRIAS (Prostate Cancer Research International: Active Surveillance) study were followed for at least 1 year and had DW-MRI scans taken in addition to repeat biopsy. Spearman's correlations were analysed between tumour appearance on DW-MRI and clinical variables [age, prostate-specific antigen (PSA), free PSA, PSA doubling time, prostate volume, percentage of cancer at diagnostic biopsy]. The Pearson chi-squared test clarified associations between outcome factors (number of positive cores and Gleason score on repeat biopsy, treatment change) and DW-MRI results. Assumed predictors of deferred radical treatment were examined with logistic regression analysis. Accuracy of tumour localization by DW-MRI compared to repeat biopsy findings was analysed by the chi-squared test.
Results: DW-MRI revealed an anatomical lesion suggestive of cancer in 40 patients (50%). MRI positivity showed no significant correlation with clinical variables. No associations existed between tumour appearance on DW-MRI and biopsy findings or discontinuation of AS. The only variable predicting treatment change was higher PSA at discontinuation (p = 0.002). Appearance of tumour, either on T2-weighted MRI (p = 0.273) or on apparent diffusion coefficient maps (p = 0.691), was not a significant predictor of treatment change.
Conclusions: Localized low-grade prostate cancer is challenging to visualize in DW-MRI, and this imaging technique provides no additional prognostic benefit compared to PSA and repeat biopsies.
Written by:
Vasarainen H, Lahdensuo K, Savolainen R, Ruutu M, Taari K, Rannikko A. Are you the author?
Departments of Urology 2 Radiology, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland.
Reference: Scand J Urol. 2013 Jan 17. Epub ahead of print.
doi: 10.3109/21681805.2013.765910
PubMed Abstract
PMID: 23327661
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