Improved identification of patients with oligometastatic clear cell renal cell carcinoma with PSMA-targeted 18 F-DCFPyL PET/CT.

OBJECTIVE: Complete surgical resection of metastatic sites has been shown to prolong survival in select patients with oligometastatic RCC. This treatment strategy is dependent upon the accurate characterization of a patient's extent of disease. The objective of this study was to explore the utility of PSMA-targeted 18 F-DCFPyL PET/CT in patients with presumed oligometastatic clear cell RCC.

METHODS: This is a subset analysis of a prospective study in which patients with RCC were imaged with 18 F-DCFPyL PET/CT (ClinicalTrials.gov identifier NCT02687139). In the present analysis, patients with oligometastatic clear cell RCC, defined as ≤ 3 metastatic lesions on conventional imaging, were evaluated. 18 F-DCFPyL PET/CT scans were reviewed for sites of disease and compared to conventional imaging.

RESULTS: The final cohort included 14 patients with oligometastatic clear cell RCC. Conventional imaging revealed 21 metastatic lesions and 3 primary tumors. 18 F-DCFPyL PET/CT detected 29 sites of metastatic disease and 3 primary tumors. Of the 21 metastatic lesions detected on conventional imaging, 17 (81.0%) had radiotracer uptake. Additionally, all 3 primary tumors had radiotracer uptake. In 4 (28.6%) patients a total of 12 more lesions were identified on 18 F-DCFPyL PET/CT than conventional imaging. Notably, 3 (21.4%) patients were no longer considered oligometastatic. The detection rates of conventional imaging and 18 F-DCFPyL PET/CT for identifying sites of disease were 66.7% and 88.9%, respectively.

CONCLUSIONS: PSMA-targeted PET/CT appears to aid in the identification of patients with oligometastatic clear cell RCC. If borne out in future studies, this suggests that PSMA-targeted imaging has the potential to help select candidates for metastasis-directed therapy.