Purpose: To explore patterns of node distribution in nasopharyngeal carcinoma (NPC) based on the 2013 updated guidelines for neck node levels.
Methods and materials: We retrospectively reviewed the imaging documents of 3100 cases of newly diagnosed NPC between January 2010 and January 2013. All patients received an MRI scan. The scan range extended from 2 cm above the anterior clinoid process to the inferior margin of the sternal end of the clavicle. All MR images were evaluated by the multi-disciplinary treatment group of NPC.
Results: A total of 2679 (86.4%) cases had involved lymph nodes. The detailed distribution was: level Ia 0, level Ib 115 (4.3%), level IIa 1798 (67.1%), level IIb 2341 (87.4%), level III 1184 (44.2%), level IVa 350 (13.1%), level IVb 28 (1.0%), level Va,b 995 (37.1%), level Vc 49 (1.8%), level VI 0, level VIIa 2012 (75.1%), level VIIb 178 (6.6%), level VIII 53 (2.0%), level IX 2, level Xa 2, level Xb 3. Among patients with level VII involvement, only 6 (0.3%) were located at the medial group. Of the patients with level II disease, the upper borders of metastatic nodes in 25.9% cases were beyond the caudal edge of C1. Patients with level VIII, or IX, or X node metastasis were always with extensive ipsilateral lymphadenopathy, and the total number of involved nodes was ⩾6. There were 35 cases of lymphadenopathy beyond the range of the updated guidelines, located inside the trapezius muscles, but posterior to level V.
Conclusions: This is the first description of nodal spread patterns based on the updated consensus guidelines. Involvement of the retropharyngeal nodes was mainly located at the lateral group, the medial group was rarely seen. The suggested upper border of level II cannot fully cover all the involved level II nodes. The posterior level V border is not enough to cover all level V lymphadenopathies for NPC.
Keywords: Clinical target volume; Consensus guidelines; Magnetic resonance imaging; Nasopharyngeal carcinoma.
Copyright © 2015. Published by Elsevier Ireland Ltd.