18F-FDG PET/CT imaging for an early assessment of response to sunitinib in metastatic renal carcinoma: preliminary study.

Purpose: Sunitinib is a new standard for the treatment of metastatic renal-cell carcinoma (RCC). We evaluated the accuracy of 18-fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) in assessing early response to this antiangiogenic drug, which cannot be obtained with conventional CT. Procedures: Patients had an FDG-PET/CT at baseline and another one for follow-up at the end of the first cycle (at day 42). For each examination, all lesions were registered and the maximum standardized uptake value (SUVmax) was measured. The metabolic response on PET at day 42 was assessed, using European Organization for Research and Treatment of Cancer criteria. Morphologic response on CT at day 84 (after two cycles), using Response Evaluation Criteria in Solid Tumors criteria, was used as the reference standard. The long-term outcome was assessed by the progression-free survival. Results: Twelve (12) patients who completed at least two cycles of sunitinib were assessed. The SUVmax for the lesi...