Efficacy of the apparent diffusion coefficient value for predicting biochemical recurrence in patients with high-risk prostate cancer

Abstract

Abstract Efficacy of the apparent diffusion coefficient value for predicting biochemical recurrence in patients with high-risk prostate cancer

Yoon Min Young Student Number : 2014-21130 Urology, College of medicine, Seoul National University

Introduction The purpose of this study was to investigate whether the apparent diffusion coefficient (ADC) value in diffusion-weighted magnetic resonance imaging (DW-MRI) could predict the prognoses of patients with high-risk prostate cancer.

Materials and methods The retrospective study included 157 patients with high-risk prostate cancer according to Damicos criteria. Patients underwent a preoperative 3-T MRI and a prostatectomy within 2 months. Patients who received neoadjuvant hormone therapy or radiation therapy were excluded. The apparent diffusion coefficient (ADC) of the tumor calculated from two b values (0, 1000 s/mm2) was measured. Areas under receiver-operating characteristics curves (AUC) were calculated to maximized the accuracy of ADC value. The cut-off point was 764 ×10-6 mm2/sec. Then, the patients were stratified into two groups: Group A consisted of patients with ADC values < 764×10-6 mm2/sec and Group B was ≥ 764×10-6 mm2/sec. Clinical and pathological outcomes were compared. The relation between the ADCmean and the BCR free survival rate were assessed by Kaplan-Meier Estimates. The Cox-proportional regression analyses were also performed.

Results Group A showed higher pathologic stage and biochemical recurrence (BCR) rates than Group B. On the Kaplan-Meier estimates, the BCR-free survival rate of Group A was much lower than that of Group B. In Cox-proportional regression analyses, ADCmean <764×10-6 mm2/sec and pathologic stage ≥T3 disease were independent predictors of BCR, whereas mean age, PSA level, pathologic Gleason score ≥8, and positive surgical margin were not significantly correlated with BCR.

Conclusion In patients with high-risk prostate cancer, ADCmean is significantly associated with BCR-free survival. ADC value is one of the useful tools to predict the prognoses of patients with high-risk prostate cancer.

Key words MRI DWI ADC, prostate cancer, high risk, prognosis, BCR free survival rate