Multi-phasic 68Ga-PSMA PET/CT in detection of early recurrence in prostate cancer patients with PSA < 1 ng/ml: a prospective study of 105 cases

Purpose: The main objective was to determine the impact of multi-phasic 68Ga-PSMA PET/CT (PSMA-scan) in the detection of local recurrence in prostate cancer patients encountering biochemical recurrence (BR) with PSA-level<1ng/ml Methods: One hundred and five patients with BR and PSA-level<1ng/ml were enrolled in this prospective study. A multi-phasic imaging including dynamic acquisition from the prostate bed, standard whole-body (WB) and delayed images were performed. Findings in each acquisition phases were assessed focusing on the detection rate of the locoregional recurrence. PSMA-scan positivity was also correlated with clinical findings.Results: Ninety-one lesions were detected in 47.6% of patients. A consensus of PSMA-scan findings and/or other clinical data was used for the interpretation of detected lesions. The detection rates were 27.8%, 45.0%, and 66.7% for PSA<0.2ng/ml, 0.2≤PSA< 0.5 and 0.5≤PSA<1, respectively. WB showed a significantly higher detection rate in the pelvic region in comparison with dynamic phase. Considering the same field of view (pelvic region), no significant difference in PSMA-scan positivity was demonstrated between WB and delayed imaging. The review of findings in all phases resulted in a better determination of equivocal lesions leading to higher diagnostic accuracy in 21.9% of patients. PSMA-scan positivity was correlated with trigger-PSA and history of anti-androgen treatment.Conclusion: PSMA-scan revealed promising results for early detection of a recurrent disease even in patients with 0.5≤PSA<1ng/ml. Stand-alone dynamic imaging seems inadequate in the detection of locoregional recurrence. However, performing multi-phasic PSMA-scan may provide additional information leading to a better determination of findings in about 20% of the cases.

کلیدواژه ها:

Prostate cancer recurrence ، 68Ga-PSMA PET/CT ، multi-phasic imaging