Background & objective: Nodal metastasis pattern of nasopharyngeal carcinoma (NPC) influences treatment planning. This study was to compare the diagnostic value of integrated positron emission tomography-computed tomography (PET-CT) with that of magnetic resonance imaging (MRI) in detecting nodal metastasis of NPC, and explore the regulation of nodal metastasis of NPC.
Methods: Clinical data of 105 NPC patients, treated in Cancer Center of Sun Yat-sen University from Jun. 2003 to May 2004, were analyzed. All patients underwent PET-CT and MRI. Findings of PET-CT and MRI were evaluated with the results of follow-up. Distribution of metastatic nodes in different nodal groups was assessed.
Results: Among the 105 patients, nodal metastasis patterns shown on PET-CT and MRI were diverse in 35 patients. Thirty cervical nodes were positive on PET-CT, but negative on MRI; 25 of them were later confirmed positive by follow-up. Thirty-seven cervical nodes were negative on PET-CT, but positive on MRI; 21 of them were confirmed negative by follow-up. Based on the results of follow-up, 77 patients (73.3%) had nodal involvement. Level II nodes were the most frequently involved (87.0%). Along the jugular chain, the frequencies of nodal metastases in level III, level IV, supraclavicular fossa, and level VII were 42.9%, 14.3%, 7.8%, and 1.3%, respectively. The frequency of nodal metastases in retropharyngeal nodes was 70.1%. Cervical nodes involvement without retropharyngeal nodes involvement was seen in 23 patients (29.9%).
Conclusions: The diagnostic accuracy of PET-CT in detecting nodal metastases of NPC is better than that of MRI. The nodal metastases of NPC reveal a decreasing frequency along the jugular chain. Both retropharyngeal and level II nodes are the first-echelon nodes of NPC.