Yim JH, et al. - The physicians conducted this work to determine the feasibility of prostate imaging-reporting and data system (PI-RADS) v2 and apparent diffusion coefficient (ADC) in assessing patients with insignificant prostate cancer (PCa), who are suitable for active surveillance (AS). The data illustrates that prostate imaging-reporting and data system v2 together with tumor ADC may be a useful marker for predicting patients with insignificant PCa when considering AS.

Methods

• This was a retrospective study.
• They recruited a sum of 238 patients with PCa who met the Prostate Cancer Research International: Active Surveillance criteria underwent radical prostatectomy.
• Insignificant cancer was characterized histopathologically as an organ-confined disease with a tumor volume <0.5 cm3 without Gleason score 4–5.
• They categorized patients into two groups based on the PI-RADS v2 and tumor ADC: A, PI-RADS score ≤3 and ADC ≥1.095 × 10-3mm2/s; and B, PI-RADS score 4–5 or ADC <1.095 × 10-3mm2/s.
• Researchers assessed preoperative clinical and imaging variables regarding the associations with insignificant cancer.

Results

• 101 (42.8%) were diagnosed with insignificant cancer on pathological findings out of the 238 patients.
• Evidence showed that the number of positive cores, prostate-specific antigen density (PSAD), PI-RADS v2 and tumor ADC were significantly correlated with insignificant cancer on univariate analysis (P < 0.05).
• Nevertheless, multivariate analysis indicated tumor ADC (odds ratio [OR]=4.57, P < 0.001) and PI-RADS v2 (OR=3.60, P < 0.001) were independent predictors of insignificant cancer.
• They further noted that area under the receiver operating characteristics curve (AUC) reached 0.803 when PI-RADS v2 (AUC=0.747) was combined with tumor ADC (AUC=0.786).