Detection of Apical Cancer with Novel Imaging Modalities to Predict Apical Margin Positivity in Robotic Assisted Radical Prostatectomy

Abstract

Objectives

To evaluate margin positivity at apex utilizing preoperative magnetic resonance imaging [MRI], micro-ultrasound [MUS], prostate specific membrane antigen positron emission tomography PSMA PET] scan, biopsy location and intraoperative timing of deep venous complex [DVC] ligation during robot assisted radical prostatectomy [RARP].

Methods

Institution review board approved retrospective study underwent RARP between November 2022 to March 2024. All patients underwent preoperative MRI, MUS and PSMA PET scan. Patients underwent RARP using either standard DVC [done prior apical dissection] ligation or delayed DVC [after prostate removal] technique. All patients underwent intra operative frozen section analysis by an experienced genitourinary pathologist. Descriptive statistics were performed. Data analyzed using R software version 4.3.3.

Results

Total 619 prostate cancer patients underwent RARP. Of these, 365 men underwent RARP using delayed DVC ligation technique and 254 men using standard DVC ligation technique. There was no statically significant difference in 2 groups on demographic parameters, MRI, MUS and PSMA-PET scan features. Sensitivity of MRI, MUS, PSMA-PET and prostate biopsy for detection of apical positive margin were 66%, 81%, 81% and 73% respectively. Specificity of MRI, MUS, PSMA-PET and prostate biopsy for detection of apical positive margin were 45%, 14%, 16% and 30% respectively. When all modalities are used accumulatively, apical cancer was missed only in 1% of cases.

Conclusions

With proper preoperative understanding of apical lesion location, timing of DVC ligation [standard vs delayed] doesn't impact apical positive surgical margins. Combination of MRI, MUS, PSMA-PET and prostate biopsy reduce apical positive surgical margin rates significantly.