131I-cG250 monoclonal antibody immunoscintigraphy versus [18F]FDG-PET imaging in patients with metastatic renal cell carcinoma: a comparative study

The aims of this study were to establish the percentage of metastatic renal cell carcinoma (RCC) lesions detected by radioimmunoscintigraphy (RIS) with the chimeric monoclonal antibody I-cG250 versus positron emission tomography (PET) with F-labelled deoxyglucose ([F]FDG), and to evaluate the use of these radionuclide imaging modalities compared with routinely used imaging techniques. Twenty patients with metastatic RCC disease were examined with [F]FDG-PET and I-cG250 RIS within 1 week. Total body gamma camera images were obtained up to 120 h after injection of 232 MBq I-cG250. Total body PET scanning was performed 45-60 min after intravenous injection of 370 MBq [F]FDG. Nuclear medicine techniques were compared to routine imaging procedures. Routine imaging modalities revealed a total of 79 metastases. [F]FDG-PET and I-cG250 RIS detected 33 previously unknown metastases, of which 32 were [F]FDG positive and seven were I-cG250 positive. Of the 112 tumour lesions that were documented, [F]FDG-PET detected 69% (77 out of 112), whereas I-cG250 RIS detected only 30% (34 out of 112). In conclusion, [F]FDG-PET is superior to I-cG250 RIS in detecting metastases in patients with metastatic RCC, and therefore seems a promising tool for (re)staging patients with RCC. The usefulness of RIS with a diagnostic dose of I-cG250 seems to be restricted to selecting patients for radioimmunotherapy with I-cG250.