The value of apparent diffusion coefficient values in predicting Gleason grading of low to intermediate-risk prostate cancer

Abstract

Objectives: To investigate the diagnostic performance of the apparent diffusion coefficient (ADC) for low to intermediate-risk prostate cancer (PCa), as well as its correlation with the prognostic Gleason score (GS).

Materials and methods: Retrospective analysis of MRI images and relevant clinical data from patients with prostate disease. The differences in ADC between different GS groups were compared, and the efficacy of ADC in PCa diagnosis were analyzed. Furthermore, the diagnostic performance of the mean ADC (ADC_mean) and minimum ADC (ADC_min) values was compared.

Results: There were 1414 patients with 1631 lesions. In terms of GS, both ADC_min and ADC_mean values of the GS 4 + 3 group were significantly lower than those of the GS 3 + 4 group, GS 3 + 3 group, and the benign group, with all differences being statistically significant (p < 0.01). The AUC values for diagnosing PCa based on ADC_min and ADC_mean were 0.914 and 0.944, respectively. The corresponding diagnostic thresholds were 0.703 × 10^-3 mm²/s for ADC_min and 0.927 × 10^-3 mm²/s for ADC_mean. The magnitudes of ADC_min and ADC_mean values exhibited a negative correlation with GS values (ρ = -0.750, p < 0.001; ρ = -0.752, p < 0.001).

Conclusions: ADC values demonstrate an inverse relationship with the invasiveness of PCa, indicating that higher invasiveness is associated with lower ADC values. Additionally, ADC values exhibit high diagnostic potential, sensitivity, and specificity for distinguishing between GS 3 + 4 and GS 4 + 3 lesions. Moreover, the diagnostic value of ADC_mean is even more significant, highlighting its crucial role in the diagnosis of low to intermediate-risk PCa.

Critical relevance statement: ADC values are a valuable tool for distinguishing different levels of aggressiveness in PCa. They help in the preoperative assessment of the biological characteristics of PCa, allowing clinicians to develop personalized treatment strategies, effectively mitigating the risk of unnecessary interventions.

Key points: The preoperative GS is crucial for planning the clinical treatment of PCa. The invasiveness of PCa is inversely correlated with ADC values. ADC values play a crucial role in the accurate preoperative evaluation of low to intermediate-risk PCa, thus aiding clinicians in developing tailored treatment plans.

Keywords: Prostate cancer, Magnetic resonance imaging, Apparent diffusion coefficient, Gleason score.

Fig. 1

Flowchart of patient inclusion into the study

Fig. 2

T₂WI shows low signal (A1, B1, C1, red arrows), DWI shows high signal (A2, B2, C2, red arrows) and ADC shows low signal (A3, B3, C3, red arrows) in peripheral zone. A A 68-year-old man, PSA = 11 ng/mL, ADC_min = 0.576 × 10⁻³ mm²/s (b = 800), ADC_mean = 0.984 × 10⁻³ mm²/s (b = 800); GS 3 + 3 (HE × 40) (A4). B 67-year-old man, PSA = 7.68 ng/mL, ADC_min = 0.411 × 10⁻³ mm²/s (b = 800), ADC_mean = 0.779 × 10⁻³ mm²/s (b = 800); GS 3 + 4 (HE × 40) (B4). C A 72-year-old man, PSA = 6.4 ng/mL, ADC_min = 0.071 × 10⁻³ mm²/s (b = 800), ADC_mean = 0.748 × 10⁻³ mm²/s (b = 800); GS 4 + 3 (HE × 40) (C4)

Fig. 3

Distribution plots of ADC_min (A) and ADC_mean (B) among various GS groups

Fig. 4

ROC curves for the diagnosis of PCa using ADC_mean and ADC_min