The role of apparent diffusion coefficient metrics in prostate cancer grading

Background. Prostate cancer (PCa) is one of the most commonly diagnosed malignancies in men. Diffusion-weighted imaging (DWI) from multiparametric MRI (mpMRI), especially the apparent diffusion coefficient (ADC), provides potential for non-invasive assessment. Purpose – to evaluate the usefulness of ADC values and ADC ratios in distinguishing between low-grade and high-grade PCa among Egyptian patients. Materials and Methods. We conducted a cross-sectional study at Beni-Suef University Hospital from February to August 2021, enrolling 40 men with histologically confirmed PCa. All participants underwent mpMRI before transrectal ultrasound-guided biopsy. ADC values were extracted from both tumor and normal peripheral zone tissue, and ADC ratios were calculated. Differences between low-grade (Gleason Score 6) and high-grade (Gleason Score ≥ 7) groups were analyzed. ROC curve analysis was used to assess diagnostic performance. Results. There was no significant difference in normal tissue ADC values between low-grade and high-grade PCa. Lesional ADC values were lower in high-grade PCa but did not reach statistical significance (p = 0.109). The ADC ratio was significantly lower in high-grade PCa (0.36 ± 0.09) compared to low-grade cases (0.45 ± 0.16; p = 0.037). ROC analysis showed an AUC of 0.664, with an optimal cut-off ADC ratio of 0.44 yielding 50.0% sensitivity and 87.5% specificity. Conclusions. The ADC ratio might serve as a non-invasive imaging biomarker to differentiate PCa grade, supporting its potential role in clinical risk stratification in Egyptian PCa patients.