Prediction of biochemical recurrence following radical prostatectomy in men with prostate cancer by diffusion-weighted magnetic resonance imaging: initial results.

OBJECTIVE: To retrospectively assess the apparent diffusion coefficient (ADC) as a predictor of biochemical recurrence (BCR) after surgery in patients with localised prostate cancer.
METHODS: Enrolled in this study were 158 men who underwent surgery between 2005 and 2007 with preoperative diffusion-weighted MR imaging (DWI) at 3 T, and who received follow-up for a median of 24 months (range, 12-57 months). Univariate and multivariate analyses including all clinical variables and tumour ADC data were performed with respect to BCR. Receiver operating characteristic (ROC) analysis was also performed to assess diagnostic performance of variables in the prediction of BCR.
RESULTS: Thirty patients (19%) who received surgery had BCR. Univariate analysis revealed that tumour ADC, Gleason score at biopsy and surgical specimen, serum PSA, greatest percentage of cancer in biopsy core, percentage of positive cores in all biopsy cores and tumour volume were all significantly related to BCR. However, multivariate analysis identified tumour ADC as the only independently predictive factor. For predicting BCR, area under the curve for tumour ADC was 0.755, and tumour ADC showed better diagnostic performance than that of all other variables.
CONCLUSION: Tumour ADC on DWI may be a predictive biomarker for BCR following radical prostatectomy.