Utility of Ga68 prostate‐specific membrane antigen positron‐emission tomography for pre‐operative staging of high‐risk prostate cancer in a prospective cohort

Utility of Ga68 prostate‐specific membrane antigen positron‐emission tomography for pre‐operative staging of high‐risk prostate cancer in a prospective cohort:

Abstract

Introduction

To assess the yield of Ga68 PSMA PET/CT added to the conventional staging of high‐risk prostate cancer in terms of altered staging and changes to management.

Methods

Patients with high‐risk prostate cancer without metastatic disease on conventional staging referred for Ga68 PSMA PET/CT at Mercy Radiology, Auckland, New Zealand, were prospectively recruited. Conventional staging was double read in a blinded fashion by oncology fellowship‐trained radiologists, who were also experienced in PET/CT, followed by interpretation of the PSMA PET/CT by the same radiologists. Confirmation of changes in management decision was obtained from the treating surgeon and multidisciplinary team meeting records. Ethical approval was obtained from the Health and Disability Ethics Committee. All patients gave written informed consent.

Results

A total of 49 patients were scanned. Three who were otherwise eligible for radical prostatectomy elected alternative treatments, leaving 46 patients included for analysis in the study. The addition of PSMA PET/CT was associated with highly statistically significant changes in both staging and management. The stage was changed in 32.6% (95% CI 20.8–47.1%, P < 0.001) patients upstaging in 60% and downstaging in 40%; clinical management in 34.8% (95% CI 22.6–49.3%; P < 0.001), with intramodality change in 25% and intermodality change in 75%. Factors predictive of a change in management with PSMA PET/CT included higher Gleason score and a greater proportion of prostatic cores positive for tumour.

Conclusion

The addition of Ga68 PSMA PET/CT to conventional staging in high‐risk prostate cancer frequently leads to changes in staging and management.