Objective: Molecular imaging with positron emission tomography (PET) provides a powerful means of identifying and characterizing cancerous processes, as well as providing a quantitative framework within which response to therapy can be ascertained. Unfortunately, the most commonly used PET radiotracer, 18F-fluorodeoxyglucose (FDG), has not demonstrated a definitive role in determining response to therapy in metastatic renal cell carcinoma (RCC). As a result, new radiotracers able to reliably image RCC could be of tremendous value for this purpose. Methods: Five patients with known metastatic RCC were imaged with the low-molecular weight radiotracer 18F-DCFPyL, an inhibitor of the prostate-specific membrane antigen at 60 min post injection. 18F-DCFPyL PET/CT and conventional images (either contrast-enhanced computed tomography or magnetic resonance imaging) were centrally reviewed for suspected sites of disease. Results: In all five patients imaged, sites of putative metastatic disease were readily identifiable by abnormal 18F-DCFPyL uptake, with overall more lesions detected than on conventional imaging. These PET-detected sites included lymph nodes, pancreatic parenchymal lesions, lung parenchymal lesions, a brain parenchymal lesion, and other soft tissue sites. 18F-DCFPyL uptake ranged from subtle to intense with maximum standardized uptake values (SUVmax) for the identified lesions of 1.6–19.3. Based upon this small patient series, limited pathology and imaging follow-up of these patients suggests a higher sensitivity for 18F-DCFPyL compared to conventional imaging in the detection of metastatic RCC (94.7 versus 78.9 %). Conclusions: PSMA expression in the tumor neovasculature of RCC has been previously established and is believed to provide the basis for the imaging findings presented here. PSMA-based PET/CT with radiotracers such as 18F-DCFPyL may allow more accurate staging of patients with RCC and conceivably the ability to predict and follow therapy in patients treated with agents targeting the neovasculature.
- Positron emission tomography (PET)
- Prostate-specific membrane antigen (PSMA)
- Renal cell carcinoma (RCC)
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging