Prognostic value of 18F-FDG PET/CT before and after radiotherapy for locally advanced nasopharyngeal carcinoma

Background: The purpose of this study was to evaluate the prognostic value of maximal standard uptake values (SUVsmax) from serial fluor-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with locally advanced nasopharyngeal carcinoma (NPC).Materials and methods: From October 2002 to January 2004, 62 patients with locally advanced NPC who underwent 18F-FDG PET/CT scan before and after radiotherapy were reviewed retrospectively. We examined the association of SUVmax and the results of long-term follow-up of the patients.Results: Patients having tumors with a lower SUVmax had significantly better 5-year overall survival (OS) (P= 0.0187) and disease-free survival (DFS) (P = 0.0163) than patients with a greater SUVmax. The patients who showed with metabolic complete response had a significantly higher 5-year OS (P = 0.0237) and DFS (P = 0.0186) than patients with metabolic partial response. Poor prognosis was found in patients with the SUVmax of neck nodes larger than that at the primary tumor site (SUVmax-N > SUVmax-P) (P = 0.0440).Conclusions:18F-FDG uptake, as measured by the SUVmax before radiotherapy and metabolic response after radiotherapy, may predict the prognosis in locally advanced NPC. High 18F-FDG uptake before and after radiotherapy may be useful for identifying patients requiring more aggressive treatment.