Utility of Ga68-PSMA PET/CT in detecting biochemical recurrence of prostate cancer

Abstract Background Ga68-Prostate-specific membrane antigen (PSMA) positron emission tomography–computed tomography (PET/CT) is recommended for assessing the biochemical recurrence of prostatic cancer (PC) with higher sensitivity, specificity, and diagnostic accuracy than other conventional imaging modalities. This study aimed to evaluate the utility of Ga68-PSMA PET/CT in detecting biochemical recurrence of prostate cancer. Methods This retrospective study involved clinical records of thirty patients who had a biochemical recurrence of prostate cancer at our department for Ga68-PSMA PET/CT and were retrospectively analyzed. Results Ga68-PSMA at cutoff level ≥ 0.3 ng/dl could detect early prostate cancer relapses with 94.7% sensitivity, 81.8% specificity, 90% positive predictive value (PPV), and 90% negative predictive value (NPV); the accuracy of early diagnosis of prostate cancer relapses was 90%. The range of the biochemical recurrence-free interval among patients with relapse was 8–120 months, with a mean of 44.84 ± 31.07, and it was significantly longer among patients who had no relapse ( p = 0.01). The mean biochemical-free interval for patients with prostate-specific antigen (PSA) < 0.3 ng/ml was significantly long ( p = 0.001). Several cases with PSA ≥ 0.3 ng/ml were 20 cases, with 18 of them presenting with prostate cancer relapse. In contrast, the number of cases with PSA < 0.3 ng/ml was 10 cases, in which only one of them presented with prostate cancer relapse. Conclusion Ga68-PSMA PET/CT could be a valuable imaging modality for early diagnosis and detection of the site of prostate cancer relapse among patients with biochemical recurrence.