Abstract
474
Introduction: To evaluate the prostate specific membrane antigen (PSMA) imaging based on PET/CT using 68Ga-PSMA-11 as tracer to detect metastatic lesion of clear cell renal cell carcinoma (ccRCC) and to access the risk scarification of metastatic ccRCC patients at baseline.
Methods: Eighteen ccRCC patients with suspicious metastasis were included in the analysis. The patients were classified into three group according the Memorial Sloan Kettering Cancer Center (MSKCC) and the International Metastatic RCC Database Consortium (IMRDC) prognostic models. All patients had undergone both 68Ga-PSMA-11 and 18F-FDG PET/CT within 1 week. To compare the diagnostic performance of the two imaging methods, the standardized uptake values (SUV) and tumor/non-target (T/NT) values of metastases were quantitatively analyzed.
Results: 68Ga-PSMA-11 and 18F-FDG PET/CT detected suspicious nodes in all the patients. There were totally 169 metastatic lesions (12 local recurrence, 17 bone metastases, 8 hepatic metastases, 57 lymphadenopathy, 65 pulmonary metastases, 6 soft tissue metastasis and 4 venous tumor thrombus). There was no difference for the area under curve (AUC), SUVmax, SUVmean and T/NT values between 68Ga-PSMA-11 and 18F-FDG PET/CT. The 68Ga-PSMA-11 uptake were higher than 18F-FDG in local recurrence (12.70±7.68 vs. 6.75±4.47, P=0.022, <0.05, n=12), bone metastases (10.75±5.63 vs. 7.16±4.36, P=0.040,<0.05, n=17), hepatic metastases (10.91±3.24 vs.5.69±2.95, P=0.028, <0.05, n=8), soft tissue metastases (11.65±6.04 vs.3.34±1.16, P=0.021, <0.05, n=6), but lower in pulmonary metastases (4.84±6.28vs.9.28±7.80, P=0.001, <0.05, n=65). For both the MSKCC and IMRDC prognostic models, the SUVmax and T/NT values of 68Ga-PSMA-11 PET/CT in poor-risk group were significantly higher than those in intermediate-risk (SUVmax and T/NT: P<0.005) and favorable-risk group (SUVmax and T/NT: p<0.005). Meanwhile, 18F-FDG PET/CT did not display similar trends to 68Ga-PSMA-11 PET/CT.
Conclusions: Our study demonstrates 68Ga-PSMA-11 can provide distinguished information about metastatic lesions of ccRCC compared with 18F-FDG. 68Ga-PSMA-11 PET/CT has better ability of risk stratification than 18F-FDG PET/CT as a functional imaging method.