The Correlation Between PI-RADS Score and the Detection of Prostate Cancer Using MRI-Ultrasound Fusion-Guided Transperineal Prostate Biopsy: The First Philippine Report

Abstract

Objective: MRI-Ultrasound fusion guided targeted biopsy has revolutionized the diagnosis of prostate cancer through accurate identification, localization and characterization of prostatic lesions utilizing the prostate imaging reporting and data system (PI-RADS) scoring system by multiparametric MRI (MPMRI). The fusion prostate biopsy system on the other hand, enables accurate targeting and easy access of the tumor. The study objective is to determine the detection rate of clinically-significant prostate cancer using fusion biopsy, and to establish the correlation between PI-RADS score and Gleason's score.

Patients and Methods: A retrospective cohort study was conducted to determine the correlation between PI-RADS score and the presence of prostate cancer using MRI-Ultrasound fusion guided transperineal prostate biopsy. This was carried out from June 2017 to July 2018 in a single institution. One hundred thirty five (135) men were included in this study. They presented with an elevated PSA, abnormal DRE or a previous negative prostate biopsy, but with a persistent rise in PSA. A total of 220 prostate lesions were identified. The following characteristics were measured: patient age; the size, location, the PI-RADS score of each lesion, the maximum PI-RADS score for select patients; and the Gleason score of discovered tumors.

Results: Two hundred twenty PI-RADS 3, 4 and 5 lesions were detected in 135 patients by MPMRI. 131 of the 220 lesions were scored as PI-RADS 3, 61 as PI-RADS 4 and 28 as PI-RADS 5. These lesions were biopsied using the MRI-Ultrasound fusion guided transperineal prostate biopsy system. Thirty-three out of the 131 PI-RADS 3 lesions (25.2%), 44 out of the 61 PI-RADS 4 lesions (72.1%) and 24 out of the 28 PI-RADS 5 lesions (85.7%) respectively were positive for malignancy. Overall, there were 101 (45.9%) lesions classified as PI-RADS 3 to 5 that were positive for prostate carcinoma. Seventy four (74) of the 135 patients (54.8%) were diagnosed with prostate adenocarcinoma. Nineteen out of 65 patients with a maximum score of PI-RADS 3 (29.2%), 33 of 44 with a maximum of PIRADS 4 (75%) and 22 of 26 with a maximum of PI-RADS 5 (84.6%) harbored malignancy. In terms of location, 45 of the 101 (44.6%) malignancies were in the peripheral sector, 31 (30.7%) in the anterior sector, and 25 (24.8%) in the central sector of the prostate. The mean Gleason grade of PIRADS 3, 4 and 5 lesions were 6.61, 7.73, and 7.38, respectively. Using Spearman correlation, the rho coefficient was 0.3153 (p-value =.00013) which denotes a significant positive relationship between Gleason and PI-RADS score.

Conclusion: This is the first comprehensive Philippine study on Multiparametric MRI-Ultrasound fusion-guided transperineal prostate biopsy. Present data validate the superiority of MPMRI in the identification, localization and characterization of prostate cancers. The authors also verified the positive correlation between PI-RADS score and Gleason score. Finally, they demonstrated the accuracy of the MRI- ultrasound fusion-guided transperineal prostate biopsy system in targeting prostate lesions.