Familial Nasopharyngeal Carcinoma 6

228 J. J. Lu, V. Grégoire, and S. LinTable 17.7. Incidence and distribution of cervical lymph node metastasis in NPC (In MRI Era)Clinical nodal metastasesAuthors Patients with N+ Level Ib a Level II Level III Level IV Level V OtherTang et al. 2009 786(85.1)24(3.1)590(75.1)226(28.8)56(7.1)87(11.1)6 b(0.8)Wang et al. 2009 543(87.8)21(3.9)506(93.2)237(43.7)72(13.3)200(36.8)7 b(1.3)Liu et al. 2006 215(78.2)6(2.8)174(80.9)65(30.2)16(7.4)18(8.4)4 b(1.9)Ng et al. 2004 89(88.1)2(2.2)85(95.5)54(60.7)31(34.8)24(27)13 c(14.6)Numbers within parentheses are in percentageaLevel Ia (submental) lymph adenopathy was not observed in any of these studiesbIncluding parotid lymph nodescIncluding parotid, level VI, mediastinal, and abdominal lymph nodesto include the retrostyloid space up to the base ofskull in NPC (Grégoire et al. 2006).The incidence of RLN metastasis in patients withcervical lymph adenopathy is between 75% and86.4%. And ∼25% has isolated metastasis in RLNwithout level II nodes involvement, and ∼15% ofpatients has isolated level II lymph adenopathywithout ipsilateral RLN. Therefore, metastases tothe retropharyngeal and level II lymph nodes areconsidered to be through two distinct pathways bymany authors (Ng et al. 2004; Wakisaka et al. 2000;Tang 2009) (Table 17.7).17.4.2.3Level V Lymph NodesA distinct drainage may exist between the nasopharynxto the lymph nodes in the posterior triangle ofthe neck. Isolated metastasis to Level V lymph nodesoccurs in about 10% of patients with NPC withoutany evidence of RLN and/or Level II lymph nodemetastases.17.4.2.4Level III and IV Lymph NodesLevel III contains a highly variable number of lymphnodes and receives efferent lymphatics from levels IIand V, and some efferent lymphatics from the retropharyngeal,pretracheal, and recurrent laryngeal nodes.Level IV contains a variable number of nodes andreceives efferent lymphatics primarily from levels IIIand V, some efferent lymphatics from the retropharyngeal,pretracheal, and recurrent laryngeal nodes. Theincidence of metastases to the Levels III and IV lymphnodes range between 30%–60% and 7%–35%, respectively;however, most patients with levels III and IVnodal involvement harbor disease in the retropharyngeal,level II, and/or level V lymph nodes, and isolatedadenopathy at level III and/or level IV are relativelyuncommon in NPC (Ng et al. 2004; Tang et al. 2009).17.4.2.5Level I Lymph NodesMetastasis to Level Ia lymph nodes are exceedinglyrare in NPC, and was not documented in most clinicalreports in the MRI era. However, metastasis to LevelIb lymph nodes is of clinical significance. Althoughisolated metastases to level Ib nodes are uncommon,in patients with Level II lymph adenopathy, approximately2%–4% of patients will harbor metastases inthe submandibular lymph nodes (Tang et al. 2009;Ng et al. 2004; Wang et al. 2008).17.4.2.6Supraclavicular Lymph NodesSupraclavicular region defined by Grégoire et al.(2006) includes the area bounded by the lower