Presented by: Shintaro Takahashi
Department of Urology, Kawasaki Medical School

Introduction

Japanese men differ from Western men in age of onset, biological aggressiveness, and tumor size in prostate cancer (PCa). Clinical efforts to verify its accuracy for risk stratification of PCa in Japanese men have recently started. The aim of the study was to evaluate the cancer detection rate of the Prostate Imaging and Reporting Data System (PI-RADS) version 2 (v2) in Japanese men using MR/US fusion-guided biopsy.

Materials

We collected data from a cohort of 205 men who underwent MRI-ultrasound fusion targeted biopsy for suspected PCa in our institution from August 31, 2018 to March 31, 2020. The cases with above 20.0 ng/ml on PSA value were excluded from this study. Single radiologist (TT) evaluated multiparametric MRI (mpMRI) using thePI-RADS v2 by consensus. Targeted biopsy was performed for lesions with PI-RADS categories of 1 to 5. After targeted biopsy, concurrent standard systematic 10 or 12-core systematic prostate biopsy was performed in all patients. Gleason 3 + 4 or greater was defined as clinically significant PCa (csPCa).

Results

,

The median age was 70 (45-89) years, the median PSA level was 6.71 (1.31-19.9) ng/ml. A total of 347 lesions with a mean of 1.7 suspicious lesions per patient were detected by mpMRI were classified as PI-RADS category 1 in 8 lesions, 2 in 47 lesions, category 3 in 119 lesions, category 4 in 150 lesions and category 5 in 23 lesions.  A median of 2.5 target biopsy cores per suspicious lesion were taken. Overall PCa detection rates were 0%, 8.5%, 23.5%, 64.0%, and 87.0% for PI-RADS categories 1, 2, 3, 4, and 5, respectively (p<0.001). A higher detection rate for csPCa was 0%, 2.1%, 12.6%, 40.0%, 73.9% for PI-RADS categories 1, 2, 3, 4 and 5, respectively (p<0.001). PCa and csPCa detection rate per patient basis were 63.9% and 42.9%, respectively. Among patients diagnosed csPCa by biopsy, negative or clinically insignificant PCa (cisPCa) in the systemic biopsy but csPCa in the target biopsy was observed in 21 cases (10.2%). On the other hand, negative or cisPCa in the target biopsy but csPCa in the systemic biopsy was observed in 16 cases (7.8%). CisPCa diagnosis per patient basis was observed in 43 cases (21%).  Among patients diagnosed cisPCa by biopsy, negative in the systemic biopsy but cisPCa in the target biopsy was observed in 8 cases (3.9%).

Conclusion

PI-RADS v2 using MR/US fusion-guided biopsy is significantly associated with the presence of csPCa in Japanese men. When performing systemic biopsy, the combination with target biopsy still improves the detection of clinically significant PCa above 10%, but also increased the detection of clinically insignificant PCa by about 4%.

Funding

None

Lead Authors

Yoshiyuki Miyaji, MD, PHD
Department of Urology, Kawasaki Medical School

Co-Authors

Sho Okada,
Department of Urology, Kawasaki Medical School

Masataka Abe,
Department of Urology, Kawasaki Medical School

Taisuke Jo,
Department of Urology, Kawasaki Medical School General Clinical Center

Shigehisa Tsuji,
Department of Urology, Kawasaki Medical School

Sho Kakumae,
Department of Urology, Kawasaki Medical School

Hirofumi Morinaka,
Department of Urology, Kawasaki Medical School

Hiroyasu Takasaki,
Department of Urology, Kawasaki Medical School Clinical Medical Center

Shinjiro Shimizu,
Department of Urology, Kawasaki Medical School

Tsutomu Tamada,
Department of Radiology, Kawasaki Medical School