Relationship between Gleason score and apparent diffusion coefficients of diffusion-weighted magnetic resonance imaging in prostate cancer patients.

INTRODUCTION We assessed the correlation between the apparent diffusion coefficient (ADC) and pathological Gleason score (GS) of prostate cancer patients. METHODS A total of 125 patients who underwent multiparametric magnetic resonance imaging before radical prostatectomy for prostate cancer were included in this study. ADC values were compared with different GS. We used receiver operating characteristic analysis and determined the ADC cutoff value to differentiate tumours with a GS of 6 from those with a GS ≥7. RESULTS We identified 34 patients (27.2%) with a GS of 6; 33 patients (26.4%) with a GS of 7; 22 patients (17.6%) with a GS of 8; and 36 patients (28.8%) with a GS of ≥9. The mean ADC value for disease with a GS of 6 was 0.914 ± 0.161 ×10-3 mm2/s; GS of 7: 0.741 ± 0.164 ×10-3 mm2/s; GS of 8: 0.679 ± 0.130 ×10-3 mm2/s; and GS of ≥9: 0.593 ± 0.089 ×10-3 mm2/s. An ADC value of 0.830 ×10-3mm2/s was the best cutoff value to identify prostate cancer with a GS of 6. CONCLUSIONS We observed an inverse relationship between GS and ADC value. Moreover, a cutoff ADC value may help differentiate disease with a GS of 6 from disease with a GS ≥7.