Current advances in diagnosis and surgical treatment of lymph node metastasis in head and neck cancer

Abstract

Still today, the status of the cervical lymph nodes is the most important prognostic factor for head and neck cancer. So the individual treatment concept of the lymphatic drainage depends on the treatment of the primary tumor as well as on the presence or absence of suspect lymph nodes in the imaging diagnosis. Neck dissection may have either a therapeutic objective or a diagnostic one. The selective neck dissection is currently the method of choice for the treatment of patients with advanced head and neck cancers and clinical N0 neck. For oncologic reasons, this procedure is generally recommended with acceptable functional and aesthetic results, especially under the aspect of the mentioned staging procedure. In this review article, current aspects on pre- and posttherapeutic staging of the cervical lymph nodes are described and the indication and the necessary extent of neck dissection for head and neck cancer is discussed. Additionally the critical question is discussed if the lymph node metastasis bears an intrinsic risk of metastatic development and thus its removal in a most possible early stage plays an important role.

Keywords: head and neck cancer; lymph node metastasis; lymphogenic metastasis; neck dissection.

Table 1. Topography and nomenclature according to Robbins [7]

Table 2. Incidence of locoregional metastasis of different cancers of the parotid gland

Figure 1. Topography of the cervical lymph node regions with description of the neck muscles relevant for the classification. In the preauricular region the parotid gland and in level I the submandibular gland is revealed. The accessory nerve delineates the limit between the levels IIA and B and is part of the level V.

Figure 2. Histological description of a micrometastasis of squamous cell carcinomas in the marginal sinus of a cervical lymph node, HE 200x. K = lymph node capsula. S = marginal sinus.

Figure 3. Sonographic description of a cervical lymph node metastasis with maximal diameter of 18 mm and hypoechoic central necrosis

Figure 4. Schematic description of more-step development of cervical lymph node metastasis.

a) Tumor-induced lymphangiogenesis in the intra- and peritumoral and invasion of the tumor cells in the lymphatic system, b) Development of micrometastasis in the sinus area, c) Enlarged lymph node metastases and the related change of the angio-architecture of the affected lymph node by curved displacement of the vessels near the metastasis and genesis of an avascular zone in the metastatic area, d) Extracapsular spread with description of aberrant and subcapsular vessels as well as necrotic areas in the metastatic region.

Figure 5. Extent of selective neck dissection in clinical N0 neck. a) For cancers of the oral cavity it is level I–III that has to be dissection, while for cancers of the tongue levels I–IV must be considered, b) For oropharyngeal cancers it is level II–III, c) For glottic and supraglottic cancers of the larynx it is level IIA–III, d) For hypopharyngeal cancers it is level IIA–IV.