F-18 fluorodeoxyglucose positron emission tomography in the evaluation of distant metastases from renal cell carcinoma

(Purpose) under bar: We conducted a study to fluorodeoxyglucose (FDG) positron emission tomography (PET) in the detection of distant metastases from renal cell carcinoma (RCC). (Materials and Methods) under bar: Twenty-four patients with histologically proven clear-cell RCC undergoing surgical evaluation for possible resection of recurrent disease were investigated. All patients had suspected distant metastases based on conventional imaging techniques (computed tomography and resonance imaging). A total of 36 distant metastatic sites were identified. Pathology for all sites was obtained by biopsy or after surgical resection. (Results) under bar: Histologically documented distant metastases from RCC were present in 33 sites (21 patients). Overall sensitivity, specificity, and positive predictive value of FDG-PET for the detection of distant metastases from RCC was 63.6% (21 of 33), 100% (three of three), and 100% (21 of 21), respectively. The mean size of distant metastases in patients with true-positive FDG-PET was 2.2 cm (95% CI, 1.7 to 2.6 cm) compared with 1.0 cm in patients with false-negative FDG-PET (95% CI, 0.7 to 1.4 cm; P =.001). (Conclusions) under bar: FDG-PET is not a sensitive imaging modality for the evaluation of metastatic RCC and may not adequately characterize small metastatic lesions. However, positive FDG-PET is predictive for the presence of RCC in lesions imaged, may complement anatomic radiologic imaging modalities, and may alleviate the need for a biopsy in selected situations. A negative FDG-PET, however does not rule out active malignancy. (C) 2003 by American Society of Clinical Oncology.