Biochemical recurrence (BCR) occurs in approximately 25% of patients with prostate cancer (PCa) who are treated with radical prostatectomy and up to 45% of patients who undergo external beam radiotherapy (RT).
A recent study analyzed the efficacy of 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) for detecting local or systemic disease in patients with a history of PCa who have BCR. Early diagnosis of PCa recurrence is important for successful salvage therapy in patients.
A total of 52 patients with PCa and BCR were enrolled in the study and referred for 68Ga-PSMA PET/CT. Patients were enrolled in the study between November 2017 and December 2019 from the American University of Beirut Medical Center. PSMA PET/CT performance was compared with prostate-specific antigen (PSA), PSA kinetics, primary treatment, and Gleason score.
Of the 52 patients in the study group, 34 patients (65.4%) had positive PSMA-PET/CT scans. Among those 34 patients, 8 (23.5%) received primary RT. For all patients with a positive PSMA PET, the detection rate was 2/4 (50%) for PSA <0.2, 5/10 (50%) for PSA 0.20-0.49, 3/6 (50%) for PSA 0.50-0.99, 6/12 (50%) for PSA 1.00-1.99, 8/9 (88.9%) for PSA 2.00-3.99, and 10/11 (90.9%) for PSA 4-10.
PSMA PET/CT positivity was significantly associated with PSA level at the time of PET scan, PSA doubling time, Gleason score, and TNM staging, but it did not show a meaningful correlation with radiotherapy as a primary treatment, ongoing androgen deprivation therapy, time to relapse, or initial PSA before therapy.
68Ga-PSMA PET/CT was able to successfully detect PCa recurrence in patients with BCR. Scan positivity was significantly associated with PSA level at the time of PET scan, PSA doubling time, Gleason score, and TNM staging.