[F-18] fluorodeoxyglucose positron emission tomography as a tool for early recognition of incomplete tumor destruction after radiofrequency ablation for liver metastases

Background and Objectives: To assess the value of FDG positron emission tomography (PET) for early detection of incomplete tumor destruction after radiofrequency ablation (RFA) for liver metastasis. Methods: Twenty-eight unresectable liver metastases in 17 patients were treated by RFA. Patients underwent computed tomography (CT) and FDG-PET preoperatively, at I week, I month, and 3 months postoperatively. Postoperative CT and FDG-PET at 1 week and 1 month were analyzed to identify hypervascular and hypermetabolic residual tumors at the RFA site. These results were correlated with follow-up CT and, in case of reintervention, with pathologic results. Results: In 24/28 of RFA-treated metastases, CT and FDG-PET at 1 week and 1 month showed no tumor residues. During follow-up, none of these 13 patients developed local recurrence at RFA site. In four patients, FDG-PET at 1 week and 1 month showed peripheral hypermetabolic residue after RFA, whereas CT did not revealed residual tumor. In three patients, local persistence of viable tumor cells was biopsy-proven at reintervention. In the fourth, follow-up CT showed subsequent development of a local recurrence. Conclusions: FDG-PET accurately monitors the local efficacy of RFA for treatment of liver metastases, as it early recognizes incomplete tumor ablation, not detectable on CT. (C) 2003 Wiley-Liss, Inc.