Gege Zhao, Bin Ji
AJR Am J Roentgenol . 2022 Jun 29;1-10. doi: 10.2214/AJR.21.27323. Online ahead of print.
BACKGROUND. Bone scintigraphy (BS) using 99mTc-labeled methylene diphospho-nate (99mTc-MDP) remains the recommended imaging modality for the detection of bone metastases in patients with prostate cancer (PCa). However, PET/CT using prostate-specific membrane antigen (PSMA) ligands is increasingly recognized as a means of evaluating disease extent in patients with PCa, including use as a possible stand-alone test in high-risk patients.
OBJECTIVE. The purpose of this study is to compare the diagnostic performance of 68Ga-PSMA-11 PET/CT with that of 99mTc-MDP BS for the detection of bone metastases in patients with PCa.
EVIDENCE ACQUISITION. The PubMed, Embase, and Cochrane Library databases were searched through October 2021 to identify studies reporting a head-to-head comparison of 68Ga-PSMA-11 PET/CT and 99mTc-MDP BS for the detection of bone metastases in patients with PCa. Only studies with a well-defined reference standard (including various combinations of imaging and/or clinical follow-up) were included. Pooled diagnostic performance was calculated using a bivariate random-effects model, and an AUC was derived for each test from hierarchic summary ROC analysis. The complementary roles of the two tests in identifying bone metastases in patients in whom one of the tests was negative were summarized.
EVIDENCE SYNTHESIS. Six studies with 546 patients were included. Pooled sensitivity and specificity, respectively, were 98% (95% CI, 94-99%) and 97% (95% CI, 91-99%) for 68Ga-PSMA-11 PET/CT versus 83% (95% CI, 69-91%) and 68% (95% CI, 41-87%) for 99mTc-MDP BS. The AUC was 0.99 (95% CI, 0.96-1.00) for 68Ga-PSMA-11 PET/CT and 0.85 (95% CI, 0.81-0.87) for 99mTc-MDP BS. Among 408 patients from five included studies, 68Ga-PSMA-11 PET/CT correctly identified bone metastases in 43 of 193 patients (22.3%) with negative 99mTc-MDP BS results, whereas 99mTc-MDP BS correctly identified bone metastases in four of 210 patients (1.9%) with negative 68Ga-PSMA-11 PET/CT results.
CONCLUSION. On a per-patient basis, the diagnostic performance of 68Ga-PSMA-11 PET/CT is superior to that of 99mTc-MDP BS for the detection of PCa bone metastases. Furthermore, 99mTc-MDP BS offers limited additional information in patients with negative 68Ga-PSMA-11 PET/CT results.
CLINICAL IMPACT. According to current evidence, 99mTc-MDP BS is highly unlikely to be additive to 68Ga-PSMA-11 PET/CT in identifying bone metastases in patients with PCa.
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