Diagnostic efficacy of ⁶⁸ Ga-PSMA-PET/CT scan as a single staging modality in prostate cancer: Evidence from a tertiary healthcare centre.

Abstract

e17130 Background: To explore whether the new 68 Ga-PSMA-PET/CT (Gallium-68 prostate-specific membrane antigen positron emission tomography-computed tomography) scan could be used as a single imaging modality over conventional imaging. Methods: This was a prospective study, conducted in a urology outpatient department, included 169 of 285 registered patients after obtaining informed consent. Patients who had biopsy-proven prostate adenocarcinoma, PSA (Prostate-specific antigen) ≥ 10 ng/ml, and Gleason Grade sum ≥ 7, were enrolled from July 2019 to May 2023. They underwent multiparametric MRI (mpMRI) Technetium 99m-methyl diphosphonate(99mTc-MDP) bone scan, and CT or ultrasound for conventional staging, followed by 68 Ga-PSMA-PET/CT. Furthermore, we evaluated the diagnostic efficacy, sensitivity, and specificity of 68 Ga-PSMA-PET/CT with conventional imaging. Results: The mean age of patients was 65.5 years, and the median serum PSA was 23.08 ng/ml. Most patients (147) were high-risk, and 22 were intermediate-risk. Among them, 90 underwent robotic-assisted radical prostatectomy. PSMAPET/CT showed statistically significant superiority in detecting regional lymph node invasion (37.8% vs 18.3%), non-regional lymph node invasion (17.2% vs 5.9%), and bony metastasis (23% vs 16.5%). It had comparable efficacy to conventional imaging for seminal vesicle involvement and visceral metastasis. PSMA PET/CT upstaged N and M status in 10.6 % and 8.8% of patients, respectively. In these 8.8% of cases, patients experienced an upward stage migration which led to shift in the treatment approach from curative to palliative intent for these patients. Conclusions: 68 Ga-PSMA-PET/CT is superior to conventional imaging methods and improves detection of regional lymph node, bone, and distant metastases, enhancing staging accuracy for prostate cancer.