Apparent diffusion coefficient values in prostate cancer: Association with pathological grade groups and correlation with Ki-67 proliferation index

Objectives: The objective of the study is to investigate the diagnostic value of apparent diffusion coefficient (ADC) parameters in differentiating prostate cancer (PCa) pathology grading groups (GG) and their correlation with Ki-67 proliferation index. Material and Methods: This single-center retrospective study analyzed magnetic resonance imaging data from 119 pathologically confirmed PCa cases with documented Ki-67 proliferation indices. Both mean ADC (ADCmean) and minimum ADC (ADCmin) values were obtained from dominant lesions using ADC mapping. Comparative analysis was performed between high-risk PCa (hPCa) and non-high-risk PCa (nhPCa) groups. Diagnostic performance was assessed through receiver operating characteristic (ROC) curve analysis, while Spearman correlation was employed to evaluate relationships between ADC parameters, GG, and Ki-67 index. Results: Significantly lower ADCmean and ADCmin values were observed in hPCa compared to nhPCa (P < 0.001). ROC analysis demonstrated the diagnostic utility of ADC parameters in distinguishing hPCa from nhPCa. Both ADCmean and ADCmin showed significant negative correlations with GG and Ki-67 proliferation index (P < 0.001). Conclusions: This study demonstrates an inverse correlation between ADC values and tumor proliferative activity in PCa, providing biological validation for DWI in assessing tumor aggressiveness. While this quantitative parameter shows potential for risk stratification, its application requires further multicenter validation.