The urologist's learning curve of "in-bore" magnetic resonance-guided prostate biopsy

The learning curve and experience of a novel multi-modal image fusion targeted transperineal prostate biopsy technique using electromagnetic needle tracking under local anesthesia

Background

Prostate cancer is the most common malignant tumor of male genitourinary system, and the gold standard for its diagnosis is prostate biopsy. Focusing on the methods and skills of prostate biopsy, we explored the learning curve and experience of a novel magnetic resonance imaging and transrectal ultrasound (mpMRI-TRUS) image fusion transperineal biopsy (TPB) technique using electromagnetic needle tracking under local anesthesia.

Methods

The clinical and pathological data of 92 patients who underwent targeted TPB from January 2023 to July 2023 in our center were prospectively collected. The cumulative sum (CUSUM) analysis method and the best fitting curve were used to analyze the learning curve of this novel technique, and the clinical characteristics, perioperative data and tumor positive rate of prostate biopsy of patients at different stages of the learning curve were compared.

Results

With the increase of the number of surgical cases, the overall operative time showed a downward trend. The best fitting curve of CUSUM reached its peak at the twelfth case, which is the minimum cumulative number of surgical cases needed to cross the learning curve of the operation. Taking this as the boundary, the learning curve is divided into two stages: learning improvement stage (group A, 12 cases) and proficiency stage (group B, 80 cases). The surgical time and visual analog scale score during prostate biopsy in group A were significantly higher than those in group B. The visual numerical scale score during prostate biopsy in group A was significantly lower than that in group B. There was no statistically significant difference between group A and group B in the detection rate of csPCa and the incidence of perioperative complications.

Conclusion

The novel targeted TPB technique is divided into learning improvement stage and proficiency stage, and 12 cases may be the least cumulative number.

Novel Prostate Biopsy Technique Using Imaging Fusion in a Patient With Absent Rectum

INTRODUCTION

A 70-year-old male with prior total colectomy for ulcerative colitis was referred for elevated prostate specific antigen (PSA) (8.01) with PIRADS 4 lesion on magnetic resonance imaging (MRI). Described is a novel technique using pre-operative multi-parametric prostate MRI and intraoperative computed tomography (CT) 3D/3D fusion for systematic and targeted prostate biopsy in a patient lacking a rectum.

TECHNICAL CONSIDERATIONS

Under general anesthesia, an ultra-low-dose (ULD) cone beam CT was performed in supine position using a robotic-armed fluoroscopy system (Artis Zeego Care+Clear, Siemens). 3D/3D auto-registration of the femoral heads and prostate from the MRI and ULD CT was performed. The prostate edges and two areas of concern were marked. Then, reduced-dose fluoroscopy-guided prostate biopsy was performed transperineally using triangulation technique. 27 prostate biopsy cores were obtained. Grade group 5 (Gleason 4+5=9) prostate cancer was identified in two cores from the targeted lesion and one core from the prostate base. The remaining twenty-four biopsies were negative for malignancy. Surgical time was 81 minutes. PSMA scan demonstrated no metastasis or lymphadenopathy. Robotic-assisted laparoscopic radical prostatectomy was performed without complications. Final pathology demonstrated T3a, grade group 5 prostate adenocarcinoma involving 10% of the prostate volume with negative surgical margins.

CONCLUSION

This is the initial report of fluoroscopy-guided prostate biopsy using imaging fusion techniques in a patient without a rectum. This technique allowed precise identification of localized, very high-risk prostate cancer with over three times the number of cores, and much lower radiation dose, than typical CT-guided biopsies. Our technique could provide a new paradigm in targeted prostate biopsy.

The influence of the operator's experience on the outcomes of fusion prostate biopsy

Introduction

Magnetic resonance imgaing (MRI) targeted biopsy is the gold standard for prostate cancer (PCa) diagnosis. In this study, we examined the association between the operator's experience and the improvement in the precision of the MRI prostate biopsy procedure and the detection of PCa.

Material and methods

We included consecutive patients who underwent prostate fusion biopsy. Data on biopsy duration, prostate-specific antigen (PSA) value, lesion size, number of samples taken, number of cores involved, and International Society of Urological Pathology (ISUP) grade were subjected to statistical analysis, with the study group divided into three consecutive time periods (tertiles).

Results

There were statistically significant differences in biopsy duration between tertiles (p <0.001). The greatest difference in the involved/taken cores ratio occurred between the first and third tertile (p = 0.002). The difference between the first and second tertile was insignificant (p = 0.4), while the difference between the second and third tertile was statistically significant (p = 0.004). The differences between tertiles in Prostate Imaging and Reporting Data System v2.1 were also significant (p = 0.003). The PSA value (p = 0.036) was statistically significant, unlike prostate volume (p = 0.16), digital rectal examination (DRE) (p = 0.7), and ISUP grade (p = 0.7). There was no statistical difference between tested tertiles in the number of detected PCa ISUP ≥2 (Z = 0.191; p = 0.8).

Conclusions

The abilities and precision of the operator increase with the increase in the number of procedures performed. The biopsy duration is shortened, and the detection of PCa during the procedure seems to improve with the operator's experience.