Correlation of gallium-68 prostate-specific membrane antigen positron emission tomography - Computed tomography/magnetic resonance imaging with histopathology characteristics in carcinoma prostate patients undergoing radical prostatectomy.

INTRODUCTION

Gallium-68 prostate-specific membrane antigen positron emission tomography (Ga-PSMA PET) is being increasingly used in patients with prostate cancer (PCa) for the staging and detection of lymph node (LN) metastases, despite a lack of prospective, validated evidence. We aimed to investigate the relationship between the PSMA PET findings (maximum standardized uptake [SUV] value) and the final histopathology results (Gleason Grade [GG], and LN positivity) in patients undergoing radical prostatectomy.

METHODS

This is a single centre, prospective, observational study of 63 consecutive eligible patients treated at a tertiary care centre in India. Patients underwent Ga-PSMA PET computed tomography with fusion magnetic resonance imaging for staging, followed by a Transrectal ultrasound guided prostate biopsy. All patients underwent robotic-assisted radical prostatectomy with extended pelvic LN dissection as per the standard protocol. Clinical parameters and SUV values were collected and analysed.

RESULTS

The median preoperative prostate specific antigen (PSA) was 15.0 ng/ml (interquartile range: 9.4-28.0). A statistically significant correlation was observed between the PSA values and the SUV uptake ( < 0.001). Additionally, there was a statistically significant correlation between the SUV of the prostatic lesion and the GG on the radical prostatectomy specimens ( = 0.025), and SUV of LN and LN involvement ( < 0.001). The sensitivity and specificity of the Ga-PSMA PET scan were 77.8% and 88.7%, respectively.

CONCLUSIONS

SUVmax of the PCa lesion and the GG Group on the final histopathology correlates significantly. There is an increased SUV uptake in Gleason's Score (GS) 8, 9 tumours as compared to GS 6 and 7.