Head-to-head comparison between 18F-FDG and 18F-PSMA-1007 PET/CT in diagnosing recurrent and metastatic prostate cancer.

BACKGROUND

This study aimed to perform a head-to-head comparison of the diagnostic efficacy between fluorine-18 prostate-specific membrane antigen-1007 (18F-PSMA-1007) and fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in detecting recurrent and metastatic lesions in patients with prostate cancer (PCa).

METHODS

This retrospective study included 87 patients with recurrent and metastatic who underwent both 18F-FDG and 18F-PSMA-1007 PET/CT within 14 days. The site-specific detection rates and patient-based diagnostic efficacy were compared. The semiquantitative parameters (SUVmax and lesion-to-background ratios) were analyzed. Correlations between serum prostate-specific antigen (PSA) levels and SUVmax, SUVmean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were assessed. The influence of PSA levels on diagnostic performance was also evaluated.

RESULTS

The overall detection rate of 18F-PSMA-1007 PET/CT was significantly higher than that of 18F-FDG PET/CT [83.9% vs. 51.7%, P < 0.001]. 18F-PSMA-1007 demonstrated superior detection for prostate bed (34.5% vs. 9.2%, P < 0.001), bone metastases (66.7% vs. 32.2%, P < 0.001), and distant metastases (11.5% vs. 3.4%, P = 0.044), but not for nodal involvement (23.0% vs. 14.9%, P = 0.176). ¹⁸F-PSMA-1007 PET/CT had significantly higher sensitivity (90.74% vs. 57.41%), NPV (54.55% vs. 23.33%) and overall diagnostic accuracy (88.71% vs. 61.29%) than ¹⁸F-FDG; ¹⁸F-FDG had higher specificity (87.50% vs. 75.00%), with both tracers showing high PPV (98.87% and 96.08%, respectively). Among the 41 patients with concordantly positive lesions, 18F-PSMA-1007 exhibited significantly higher SUVmax, lesion-to-aorta ratio, and lesion-to-muscle ratio (all P < 0.05). 18F-PSMA-1007 showed superior detection performance in patients with PSA ≤ 2.0 ng/mL (73.47% vs. 38.78%, P < 0.001), with no significant difference in those with PSA > 2.0 ng/mL (84.21% vs. 68.42%, P = 0.105). MTV and TLG measured using 18F-PSMA-1007 PET/CT showed moderate correlation with PSA levels (r = 0.431, P = 0.005 and r = 0.469, P = 0.002, respectively).

CONCLUSIONS

18F-PSMA-1007 PET/CT outperformed 18F-FDG PET/CT in diagnostic efficacy for detecting recurrent and metastatic PCa, with the greatest advantage observed in patients with low PSA levels (≤ 2.0 ng/mL).