Pretreatment 18F-FDG PET standardized uptake value of primary tumor and neck lymph nodes as a predictor of distant metastasis for patients with nasopharyngeal carcinoma

Abstract

To evaluate the prognostic value of maximum standardized uptake value (SUVmax) measured in [(18)F]-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) for patients with non-disseminated nasopharyngeal carcinoma (NPC). From January 2002 to July 2008, 371 NPC patients who underwent (18)F-FDG-PET before radical intensity-modulated radiotherapy (IMRT) were recruited. The SUVmax was recorded for the primary tumor (SUVmax-T) and neck lymph nodes (SUVmax-N). The median follow-up was 64months. The optimal cutoff value was 9.3 for SUVmax-T and 7.4 for SUVmax-N. Patients with a lower SUVmax-T or SUVmax-N had a significantly better 5-year distant metastasis-free survival (DMFS), but showed no significant difference in local control or regional control. Patients were divided into four groups by SUVmax, as follows: (a) both lower SUVmax-T and SUVmax-N, (b) higher SUVmax-T only, (c) higher SUVmax-N only, and d) both higher SUVmax-T and SUVmax-N. There were significant differences between these four groups in 5-year DMFS: (a) 95.5%, (b) 90.0%, (c) 83.3%, and (d) 79.9%, respectively (p=0.004). When looking at the stage of disease, the 5-year DMFSs in group a, b, c, d were 96.9%, 94.6%, 97.4%, and 84.3%, respectively in stage I-III patients (p=0.037) and were 91.6%, 82.9%, 68.5%, and 76.7% in stage IVA-B patients (p=0.145). Using multivariate analysis, the SUVmax grouping, gender, and stage were independent factors for DMFS. The SUVmax of the primary tumor and neck lymph nodes were independent prognostic factors for DMFS in NPC patients treated with IMRT.