OBJECTIVETo explore the relation of the standard uptake values (SUV) of 18F-fluorodexygl-gucose (18F-FDG) PET/CT and the pathological classification and clinical staging of nasopharyngeal carcinoma (NPC).

METHODWhole body 18F-FDG PET imaging was performed in 32 patients with pathologically confirmed NPC, who received no previous treatment. The regions of interest (ROI) covering the pharyngeal and cervical lesions were defined along the margins of the lesion, and the lesion volume and the SUVs were calculated.

RESULTSThe SUVs in stage I, II, III, and IV patients were 4.50-/+0.42, 5.62-/+1.44, 7.33-/+1.50, and 8.24-/+2.16, respectively, showing significant differences between them (P < 0.05). In patients in stage T1, T2, T3, and T4, the SUVs increased significantly in advanced stageds (2.56-/+1.05, 3.72-/+0.60, 6.87-/+1.07, and 9.70-/+0.70, respectively, P < 0.05). The SUVs were not significantly different in patients in stages N1, N2, and N3, differed significantly between lymph nodes > 6 cm in size and those < or = 6 cm (5.92-/+1.51 vs 3.48-/+1.31, P < 0.05). The SUV in poorly differentiated squamous carcinoma was significantly lower than that in undifferentiated carcinoma (5.58-/+1.48 vs 8.41-/+1.71, F = 1.3323, P = 0.01).

CONCLUSIONSThe SUV is not associated with the clinical staging of NPC, but is correlated to the T staging of NPC. Though irrelevant to the N staging of NPC, the SUV is correlated to the size of the lymph nodes, and also related to the degree of differentiation of NPC.