Is endorectal coil necessary for the staging of clinically localized prostate cancer? Comparison of non-endorectal versus endorectal MR imaging

Purpose: The goal of this study was to compare the diagnostic use and safety of endorectal coil (ERC) MRI with those of phased-array coil MRI. Methods: We retrospectively included 91 consecutive patients who had undergone 1.5-T MRI with ERC or with phased-array coil MRI before radical prostatectomy at our institution. We compared 47 patients' phased-array coil MRI and 44 patients' ERC-MRI with histologic findings. We also evaluated adverse events following the MRI procedure. Results: The serum PSA levels ranged from 2.85 to 33.51 ng/mL (10.72 ± 1.9), and the median Gleason score was 7 (range 4-9). The mean interval between diagnostic prostate biopsy and staging MRI was 18.4 days (range 2-37). In assessing organ-confined disease, extracapsular extension and seminal vesicle invasion by MRI, there were no significant differences between ERC-MR group and phased-array coil MR group. The AUC values were 0.671 (95% CI 0.530-0.813) for ERC-MR and 0.657 (95% CI 0.503-0.811) for phased-array coil MR. No significant differences were found between the two groups (p = 0.24). Five patients (11.4%) developed rectal complications after ERC-MRI. However, no complications were found in phased-array coil MRI group. Conclusions: In terms of diagnostic accuracy and comfort of patients, the use of ERC-MRI did not significantly improve the staging of prostate cancer and presented several complications. Therefore, phased-array coil MRI is a better alternative considering comorbidity.