68Ga-PSMA PET/CT for Patients with PSA Relapse after Radical Prostatectomy or External Beam Radiotherapy

Finn Edler von Eyben; Cigdem Soydal; Rie von Eyben

doi:10.3390/diagnostics11040622

⁶⁸Ga-PSMA PET/CT for Patients with PSA Relapse after Radical Prostatectomy or External Beam Radiotherapy

Diagnostics (Basel). 2021 Mar 30;11(4):622. doi: 10.3390/diagnostics11040622.

Authors

Finn Edler von Eyben¹, Cigdem Soydal², Rie von Eyben³

Affiliations

¹ Center of Tobacco Control Research, 5230 Odense, Denmark.
² Department of Nuclear Medicine, Ankara University, 06560 Ankara, Turkey.
³ Department of Radiation Oncology, Stanford University, Stanford, CA 94350, USA.

Abstract

The study aimed to summarize clinical characteristics associated with Gallium-68-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (⁶⁸Ga-PSMA PET/CT) scans as patients were restaged for prostate-specific antigen (PSA) relapse after radical prostatectomy (RP) or external beam radiotherapy (EBRT). Our analyses included multiple cox regression analyses. The study evaluated 95 patients with rising values of PSAs after RP and after EBRT. Sixty 63% of patients had a positive ⁶⁸Ga-PSMA PET/CT scan. Twelve patients (13%) had a positive site in the prostate bed, 29 patients (30%) had a positive site in the regional lymph nodes, and 19 (20%) had positive sites in distant organs. After four years follow-up, 21 patients (22%) died. Using multiple Cox regression analyses, the number of positive sites on the ⁶⁸Ga-PSMA PET/CT scan significantly predicted overall survival (OS) (p = 0.0001), whereas risk score and regional locations of the positive sites were not significant in the multiple Cox regression analyses. Our study indicates that the specific findings of ⁶⁸Ga-PSMA PET/CT scans are important because detailed findings of the scans predict the outcome after salvage treatment of patients with PSA relapse examined with ⁶⁸Ga-PSMA PET/CT scans.

Keywords: 68Ga-PSMA positron emission tomography/computed tomography (PET/CT); non-metastatic prostate cancer; oligometastatic prostate cancer; overall survival (OS); prostate-specific antigen (PSA) relapse; prostate-specific membrane antigen (PSMA); salvage treatment.