Guidelines for delineation of lymphatic clinical target volumes for high conformal radiotherapy: head and neck region

  • Hilke Vorwerk1, 2Email author and

    Affiliated with

    • Clemens F Hess1

      Affiliated with

      Radiation Oncology20116:97

      DOI: 10.1186/1748-717X-6-97

      Received: 14 April 2011

      Accepted: 19 August 2011

      Published: 19 August 2011

      Abstract

      The success of radiotherapy depends on the accurate delineation of the clinical target volume. The delineation of the lymph node regions has most impact, especially for tumors in the head and neck region. The purpose of this article was the development an atlas for the delineation of the clinical target volume for patients, who should receive radiotherapy for a tumor of the head and neck region. Literature was reviewed for localisations of the adjacent lymph node regions and their lymph drain in dependence of the tumor entity. On this basis the lymph node regions were contoured on transversal CT slices. The probability for involvement was reviewed and a recommendation for the delineation of the CTV was generated.

      Introduction

      The major problem in radiation treatment with IMRT technique is the failure to select and delineate the target accurately, especially in patients with head and neck cancer, in which a high risk of subclinical nodal disease exists. CT-based investigation is not sufficient to detect metastases smaller than one centimetre in diameter [1]. Since the lymph node status is the most important prognostic factor in patients with squamous cell cancer in the head and neck region, and due to the limitation of clinical staging, other factors, like histopathologic examinations, may help to predict metastatic lymph node involvement [13].

      The lymphatic migration of tumor cells is usually stepwise and occurs in a predictable manner [46]. Detailed anatomical knowledge of the lymphatic network associated with each area of the body is essential to define all the sides in which the presence of metastatic nodes should be investigated and to delineate on a morphological basis the optimal target volume to be treated by high conformal radiotherapy [5, 7]. An optimization of radiation techniques to maximize local tumor control and to minimize side effects in radiotherapy of head and neck tumors requires proper definition and delineation guidelines for the clinical target volume (CTV). Most previous results are consensus guidelines from different physicians [2, 8, 9].

      The purpose of this article was to define the lymphatic CTV for the radiation treatment on a CT based atlas for tumors of the head and neck region to have a principle recipe for the delineation for clinical use. This atlas displays the clinically relevant nodal stations and their correlation with normal lymphatic pathways on a set of CT images.

      General anatomy

      The main nasal cavity includes the cavities of the interior nose between the vestibule of the nose and the Choana (Figure 1). The oral vestibule is located between the teeth and the lips and the cheek respectively. The alveolar process border the oral cavity lateral and ventral, whereas the velum and palatine border the oral cavity to the cranial side (Table 1). The caudal limit is the floor of the mouth. The pharynx is defined as the region of the combined respiratory and digestive system, which is located dorsal of the oral cavity and nasal cavity, incipient cranial at the skull base up to caudal at the beginning of the esophagus and the trachea. The pharynx is divided into three regions - nasopharynx, oropharynx and hypopharynx. The exact limits between these regions are not definitely defined. The nasopharynx is located at the cranial part of the pharynx and ends caudal at the velum palatinum. The nasopharynx includes the pharyngeal tonsil. The next section of the pharynx is the oropharynx, which ends at the top of the epiglottis. The third part of the pharynx is the hypopharynx, which begins cranial of the larynx and ends at the cranial ending of the cricoid cartilage behind the larynx. The larynx is subdivided into three parts: supraglottis, glottis and subglottis. The supraglottis is the vestibulum of the larynx, beginning at the entrance of the larynx down to the fissure between the plicae vestibulares. The glottis is the intermediate cavity between the rima vestibule and the glottis opening. The most caudal laryngeal region down to the entrance of the trachea is the subglottis (infraglottic cavity).
      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig1_HTML.jpg
      Figure 1

      Anatomic head and neck regions contoured on a sagittal DRR and transversal CT slices.

      Table 1

      Anatomic head and neck regions

      anatomic region

      description

      nose and paranasal sinus

      main nasal cavity

       

      vestibule of the nose

       

      maxillary sinus

      oral cavity

      gingiva

       

      hard palate

       

      buccal mucosa

       

      floor of the mouth

       

      ventral 2/3 of the tongue

       

      oral vestibule

       

      lips

      salivary glands

      parotid gland

       

      submandibular gland

       

      sublingual gland

      nasopharynx

      posterior wall of the pharynx beginning at the threshold between the soft and hard palatine up to the base of the skull

       

      nasal surface of the soft palatine

       

      palatine tonsil

      oropharynx

      pharyngeal tonsil

       

      arcus palatinus

       

      root of the tongue

       

      vallecula epiglottica

       

      posterior wall of the oropharynx

       

      oral surface of the soft palatine

       

      uvula

      hypopharynx

      posterior wall of the pharynx between the upper border of the epiglottis and the esophagus

       

      post cricoid region

       

      sinus piriformis

      larynx

      cricoid cartilage

       

      thyroid cartilage

       

      cartilages arytaenoideae

       

      epiglottis

      Lymph drainage

      The lymphatic CTV encompasses pathologic lymph nodes with a safety margin and adjacent areas, which are at risk for tumor spread. Lymph nodes should be assessed as pathologic, if their diameter is more than 1 cm, all nodes with spherical rather than ellipsoidal shape, nodes containing inhomogeneities (suggestive of necrotic centers) or a cluster of three or more borderline nodes. In the node positive patients, an important factor to consider is the probability of capsular rupture and extracapsular extension. The lymphatic CTV do not only include lymph nodes (LN) with radiological criteria of involvement but also one or more adjacent lymph node regions [2, 10, 11]. The lymphatic drainage for each organ uses several pathways including the main collecting way, but also alternative routes [5]. These alternative routes should be included in the target volume definition in dependence of the feasibility for that route.

      The anatomic patterns of lymphatic drainage for different body regions to their nodal stations were taken from Richter and Feyerabend Normal lymph node topography [12] and confirmed with other anatomy textbooks [5, 1315]. The elective irradiation of N0 patients can produce results equivalent to those obtained by neck dissection. Hence we used histopathologic analyses to create our suggested guidelines [16]. The main lymphatic routes for different organs, which are relevant in radiotherapy of the head and neck region, are summarized in Table 2. A general description of the anatomic lymph node drain for different lymph node regions can be found in Table 3 and Figure 2, 3, 4, 5, 6, 7, 8. The lymph node regions are classified into lymph node level (Table 4) adapted to Som et al. [17]. Guidelines for lymphatic CTV delineation of the most frequently cases of the different tumor entities were generated and summarized in Table 5,6,7,8.
      Table 2

      Anatomy - lymph node regions

      anatomic region

      organ

      subregion

      1. lymph node region

      figure

      2. lymph node region

      nasal cavity

      nose

      anterior parts of the mucosa

      LN submandibulares

      3

      LN ventrales jugulares superiores

        

      posterior part of mucosa

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

      oral cavity

      oral cavity

      buccal mucosa, outer part of alveolar ridge

      LN submandibulares

      3

      LN ventrales jugulares superiores

        

      inner part of alveolar ridge

      LN submandibulares

      3

      LN ventrales jugulares superiores

        

      hard and soft palate

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

         

      (crossing the sides!)

      3

       
        

      gingiva of the front teeth of mandible

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN submentales

      3

      LN ventrales jugulares sup./LN submand.

        

      upper gingiva

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

         

      (crossing the sides!)

      3

       
        

      other gingiva of mandible

      LN submandibulares

      3

      LN ventrales jugulares superiores

        

      Teeth

      LN submandibulares

      3

      LN ventrales jugulares superiores

        

      floor of the mouth

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN submentales

      3

      LN ventrales jugulares sup./LN submand

      tongue

       

      tip of tongue

      LN submentales

      3

      LN ventrales jugulares sup./LN submand.

        

      lateral part of tongue

      LN submandibulares

      3

      LN ventrales jugulares superiores

        

      central and posterior part of tongue

      LN ventrales jugulares superiores

      3

       
         

      LN jugulares mediales

      3

       
        

      all

      (crossing the sides!)

        

      nasopharynx

        

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

         

      LN ventrales jugulares superiores

      5

       
         

      (crossing the sides!)

        

      oropharynx

       

      dorsal part of the oropharynx

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

         

      LN ventrales jugulares superiores

      5

       
        

      other parts

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN ventrales jugulares superiores

      3

       

      hypopharynx

        

      LN jugulares mediales

        
         

      LN paratracheales

      7

      LN jugulares mediales and inferiores

         

      LN retropharyngeales (caudal part)

      5

      LN ventrales jugulares superiores

      larynx

       

      supraglottic region

      LN ventrales jugulares superiores

      6

       
         

      LN infrahyoidei

      6

      LN jugulares mediales

        

      glottic region

      supraglottic region

      6

       
         

      subglottic region

      6

       
        

      subglottic region

      LN prelaryngeales

      6

      LN jugulares mediales

         

      LN pretracheal

      7

      LN jugulares mediales and inferiors

         

      LN paratracheales

      7

      LN jugulares mediales and inferiores

        

      posterior part of larynx

      LN paratracheales

      7

      LN jugulares mediales and inferiores

        

      all

      crossing the sides! no crossing

      between supraglottic and glottic region

        

      ear

       

      external auditory canal

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

        

      tympanic cavity

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

         

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

        

      eustachian tube

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

      orbit

       

      cornea, sclera, lens, retina

      ---

        
        

      conjunctiva

      circumferentially around cornea [circulus lymphaticus]

        
        

      lateral part of conjunctiva

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

         

      LN parotidei superficiales

      2

      LN ventrales jugulares superiores

        

      medial part of conjunctiva

      LN faciales

      3

      LN submand.

         

      LN submandibulares

      3

      LN ventrales jugulares superiores

      paranasal sinuses

        

      LN ventrales jugulares superiores

        
         

      LN retropharyngeales

      5

      LN ventrales jugulares superiores

      cellulae mastoidei

        

      LN retroauricular [ = LN mastoidei]

      4

      LN ventrales jugulares superiores

      submandibular gland

        

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN ventrales jugulares superiores

        

      parotid gland

       

      cranial part

      LN parotidei superficiales

      2

      LN ventrales jugulares superiores

         

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

        

      caudal part

      LN parotidei superficiales

      2

      LN ventrales jugulares superiores

         

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

         

      LN cervicales laterales superficiales

      4

      LN cerv. prof. lat. mediales

      thyroid gland

       

      medial superior part

      LN pretracheal

      7

      LN cerv. prof. lat. mediales and inferiores

        

      lateral superior part

      LN jugulares mediales

      7

       
        

      medial inferior part

      LN pretracheal

      7

      LN cerv. prof. lat. mediales and inferiors

         

      LN paratracheal

      7

      LN cerv. prof. lat. mediales and inferiores

         

      LN thyroidei

        
        

      lateral inferior part

      LN jugulares inferiores

      7

       

      skin

      scalp

      forehead

      LN parotidei superficiales

      2

      LN ventrales jugulares superiores

         

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN faciales

      3

      LN submand.

        

      temple

      LN parotidei superficiales

      2

      LN ventrales jugulares superiores

        

      region around the mastoid process

      LN retroauricular [ = LN mastoidei]

      4

      LN ventrales jugulares superiores

        

      parietal part of the scalp

      LN retroauricular [ = LN mastoidei]

      4

      LN ventrales jugulares superiores

        

      occipital scalp

      LN occipitales

      4

      LN dorsales jugulares superiores

       

      neck

      nape

      LN cervicales laterales superficiales

      4

      LN jugulares mediales

        

      side of the neck

      LN cervicales posteriores profundi

      8

      LN supraclaviculares

        

      ventral part of neck

      LN cervicales anteriores superficiales

      7

      LN pretracheal

           

      LN paratracheales

           

      LN jugulares inferiores

        

      skin over sternocleidomastoid

      muscle, supraclavicular, suprahyoidal, infrahyoidal region

      LN jugulares

        
       

      face

      lateral eyelid

      LN parotidei superficiales

      2

      LN ventrales jugulares superiores

         

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

        

      medial eyelid

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN faciales

      3

      LN submand.

        

      lacrimal gland

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

        

      cheek

      LN submandibulares

      3

      LN ventrales jugulares superiores

        

      lower lip

      LN submentales

      3

      LN ventrales jugulares sup./LN submand

        

      chin

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      (crossing the sides!)

        
        

      upper lip

      LN submandibulares

      3

      LN ventrales jugulares superiores

       

      nose

      root of the nose

      LN parotidei profundi

      2

      LN ventrales jugulares superiores

        

      other parts of the nose

      LN submandibulares

      3

      LN ventrales jugulares superiores

         

      LN faciales

      3

      LN submand.

       

      ear

      anterior part

      LN parotidei superficiales

      2

      LN ventrales jugulares superiores

        

      lower part

      LN cervicales laterales superficiales

      4

      LN jugulares mediales

        

      posterior part

      LN retroauricular [ = LN mastoidei]

      4

      LN ventrales jugulares superiores

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig2_HTML.jpg
      Figure 2

      Lymph regions and drain contoured in transversal CT slices: LN parotidei superficiales (pink) and LN parotidei profundi subdivided into LN preauriculares (yellow) and LN infra-/intraparotidei (light green) [1.8 cm slice thickness].

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig3_HTML.jpg
      Figure 3

      Lymph regions and drain contoured in transversal CT slices: LN buccales (brown), LN submentales (pink) and LN submandibulares (dark blue) [1.8 cm slice thickness].

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig4_HTML.jpg
      Figure 4

      Lymph regions and drain contoured in transversal CT slices: LN occipitales (white), LN retroauriculares [ = LN mastoidei] (pink), LN cervicales laterales superficiales (medium blue) and LN dorsales jugulares superiores (cyan) [1.8 cm slice thickness].

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig5_HTML.jpg
      Figure 5

      Lymph regions and drain contoured in transversal CT slices: LN retropharyngeales (red) [1 cm slice thickness].

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig6_HTML.jpg
      Figure 6

      Lymph drainage from the endolarynx contoured in transversal CT slices (red arrows) to the LN infrahyoidei (pink), LN prelaryngeales (violet), LN pretracheales (light pink) and LN paratracheales (light green).

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig7_HTML.jpg
      Figure 7

      Lymph regions and drain contoured in transversal CT slices: LN cervicales anteriores superficiales (yellow) and LN cervicales anteriores profundi subdivided into LN infrahyoidei (pink), LN prelaryngeales (violet), LN pretracheales (light pink) and LN paratracheales (light green) [1 cm slice thickness].

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig8_HTML.jpg
      Figure 8

      Lymph regions and drain contoured in transversal CT slices: LN cervicales posteriores profundi (yellow) and LN supraclaviculares (white).

      Table 3

      Anatomy - lymph node drain

      Lymph node regions

      Subgroups

      Anatomic site

      Influx

      Efflux

      Figure

      LN parotidei profundi

      LN preauriculares

      ventral of the auricle

      external auditory canal

      (partially over the LN parotidei superficiales)

      2

       

      LN intraparotidei

      medial of the parotid gland

      tympanic cavity

        
       

      LN infraparotidei

      dorsocaudal of the parotid gland

      parotid gland

      to the LN ventrales jugulares superiores

       
         

      skin of the root of the nose, the cheek, the lateral part of the eyelid and conjunctiva

        

      LN parotidei superficiales

       

      on the fascia parotidea

      skin of the anterior part of the ear, the forehead, the temple, the lateral part of the eyelid and conjunctiva

      LN ventrales jugulares superiores

      2

      LN retroauriculares ( = LN mastoidei)

       

      lateral of the mastoid process

      skin of the posterior part of the ear, the region around the mastoid process, parietal part of the scalp and from the cellulae mastoideae.

      LN ventrales jugulares superiores

      4

      LN occipitales

       

      at the linea nuchae superior

      skin at the occipital scalp

      LN dorsal jugulares superiores

      4

          

      LN cervicales laterales superficiales

       

      LN submentales

       

      ventral between the two venter of the musculus digastricus

      tip of tongue

      LN submandibulares

      3

         

      floor of the mouth

      LN ventrales jugulares superiores

       
         

      laterals of the two front teeth of the mandible

        
         

      skin of the lower lip and chin

        

      LN submandibulares

       

      adjacent to the submandibular gland

      anterior part of the nasal cavity

      LN ventrales jugulares superiores

      3

         

      skin/mucosa of the lips/cheek, palate, teeth, gingiva, lateral tongue and floor of the mouth

        
         

      skin from the forehead, nose and the medial part of the eyelid and the conjunctiva over inconstant LN faciales (LN buccales)

        

      LN facials (inconstant)

       

      arranged around the V. angularis

      skin from the forehead, nose and the medial part of the eyelid and the conjunctiva

      LN submandibulares

      3

      LN dorsales jugulares superiores

       

      medial of the musculus sternocleidomastoideus and dorsal of the jugular vein

      LN occipitales

      LN ventrales jugulares superiores

      4

      LN cervicales laterales superficiales

       

      along the external jugular vein, lateral of the musculus sternocleidomastoideus

      lower part of the parotid gland

      LN jugulares mediales

      4

         

      skin of the caudal part of the ear, the nape and lateral neck

        

      LN retropharyngeales

       

      in the space bounded anteriorly by the pharyngeal constrictors and posteriorly by the prevertebral Fascia, cranially by the base of the skull and caudally to the os hyoideum **

      nasopharynx

      from cranial to caudal up to the level of the os hyoideum or to the lateral side into the LN ventrales jugulares superiores

      5

         

      dorsal part of the oropharynx

        
         

      soft palate

        
         

      eustachian tube

        
         

      tympanic cavity

        
         

      dorsal part of the nasal cavity

        

      LN cervicales anteriores profundi

      LN infrahyoidei

      located on the membrane hyoidea

      cranial half of the larynx

      LN jugulares mediales

      6-7

       

      LN prelaryngeales

      on the ligamentum cricothyroideum

      caudal half of the larynx

        
       

      LN pretracheales

      at the veins thyroideae inferiors

      caudal half of the larynx

      LN jugulares mediales and inferiores

      6-7

       

      LN paratracheales

      ventral/laterodorsal of the trachea

      thyroid gland

        
       

      LN thyroidei

      at the thyroidea

      thyroid gland

      LN jugulares mediales and inferiores

       

      LN cervicales anteriores superficiales

       

      around the vein jugularis anteriores

      ventral skin of the neck

      LN pre- or paratracheales

      7

          

      LN jugulares inferiores

       

      LN cervicales posteriores profundi

       

      in the neck region caudal of the LN occipitales

      neck region

      LN supraclaviculares

      8

      LN supraclaviculares

       

      between the M. omohyoideus and the clavicular

      caudal neck

      sometimes over the venous jugulo-subclavian confluent or the thoracic duct on the left side and the lymphatic duct on the right side, to the angulus venosus [13, 14].

      8

         

      pharynx region

        
         

      trachea

        
         

      esophagus

        
         

      LN mediastinales anteriores

        
         

      LN axillares profundi

        

      **We defined the retropharyngeal level analogically to Grégoire et al. [7] and Feng et al. [27].

      Table 4

      Lymph node level (adapted to [17])

      Lymph node level

      Terminology

      Lymph node regions

      Figure

      level IA

      submental

      LN submentales

      3

      level IB

      submandibular

      LN submandibulares

      3

      level IIA

      ventral upper jugular group

      LN ventrales jugulares superiores

      2-6

      level IIB

      dorsal upper jugular group

      LN dorsales jugulares superiores

      4

      level III

      mediales jugular group

      LN jugulares mediales

      3-4, 6-7

      level IV

      lower jugular group

      LN jugulares inferiores

      6

      level VA

      posterior triangle group

      LN cervicales posteriors profundi

      8

      level VB

      posterior triangle group

      LN supraclaviculares

      8

      level VI

      anterior compartment

      LN cervicales anteriores superficiales

      6

        

      LN cervicales anteriores profundi:

      7

        

         - LN infrahyoidales

       
        

         - LN prelaryngeales

       
        

         - LN pretracheales

       
        

         - LN paratracheales

       
        

         - LN thyroidei

       

      level retropharyngeal

      retropharyngeal

      LN retropharyngeales

      5

      level parotidal

      parotidal

      LN parotidei superficiales

      2

        

      LN parotidei profundi

       

      level retroauricular

      retroauricular

      LN retroauriculares

      4

      level occipital

      occipital

      LN occipitales

      4

      level buccal

      buccal

      LN faciales

      3

      level external jugular

      external jugular

      LN cervicales laterales superficiales

      4

      Table 5

      Suggested guidelines for the treatment of the neck of patients with squamous cell carcinoma of the oral cavity or oropharynx

       

      Oral cavity cN0

          

      Oropharynx cN0

        
       

      (ventral) tongue

      floor of tue mouth

      hard palate

      upper gingiva

      lower gingiva

      buccal mucosa

      base of tongue

      tonsillar fossa

      soft palate

      pharnygeal wall (dorsal)

      submental (IA)

      b

      i

       

      i

      i

           

      submandibular (IB)

      b

      i

      b

      b

      i

      i

       

      i

      i

       

      ventral jugular sup. (IIA)

      b

      i

      b

      b

      i

      i

      b

      i

      b

      b

      dorsal jugular sup. (IIB)

            

      b

      i

      b

      b

      jugular medial (III)

      b

      i

      b

      b

      i

      i

      b

      i

      b

      b

      jugular inferior (IV)

      b

           

      b

      i

      b

      b

      cerv. post. prof. (VA)

                

      supraclavicular (VB)

                

      retropharyngeal

        

      b

      b

          

      b

      b

       

      Oral cavity cN+

          

      Oropharynx cN+

        
       

      (ventral) tongue

      floor of the mouth

      hard palate

      upper gingiva

      lower gingiva

      buccal mucosa

      base of tongue

      tonsillar fossa

      soft palate

      pharnygeal wall (dorsal)

      submental (IA)

      b

      i

      b

      b

      i

      i

          

      submandibular (IB)

      b

      i

      b

      b

      i

      i

       

      i

      i

      i

      ventral jugular sup. (IIA)

      b

      i

      b

      b

      i

      i

      b

      b

      b

      b

      dorsal jugular sup. (IIB)

            

      b

      b

      b

      b

      jugular medial (III)

      b

      i

      b

      b

      i

      i

      b

      b

      b

      b

      jugular inferior (IV)

      b

      i

      b

      b

      i

      b

      b

      b

      b

      b

      cerv. post. prof. (VA)

      b

      i

      b

      b

      i

      b

      b

      b

      b

      b

      supraclavicular (VB)

      b

      i

      b

      b

      i

      b

          

      retropharyngeal

             

      b

      b

      b

      Table 6

      Suggested guidelines for the treatment of the neck of patients with squamous cell carcinoma of the hypopharynx, larynx or nasopharynx

       

      Hypopharynx cN0

      Larynx cN0

      Nasopharynx cN0

       

      pyriform sinus

      pharyngeal wall

      esophageal extension

      supraglottic

      glottic

      subglottic

      posterior part

       

      submental (IA)

              

      submandibular (IB)

              

      ventral jugular sup. (IIA)

      b

      b

      b

      b

      b

      i

      i

      b

      dorsal jugular sup. (IIB)

             

      b

      jugular medial (III)

      b

      b

      b

      b

      b

      b

      b

      b

      jugular inferior (IV)

      b

      b

      b

      b

      b

      b

      b

      b

      cerv. post. prof. (VA)

        

      b

          

      b

      supraclavicular (VB)

        

      b

          

      b

      infrahyoidal (VI)

       

      i

      i

      b

      b

         

      prelaryngeal (VI)

       

      i

      i

       

      b

      b

        

      pretracheal (VI)

       

      i

      i

       

      b

      b

        

      paratracheal (VI)

      i

      i

      i

       

      b

      b

      b

       

      retropharyngeal

       

      b

      b

          

      b

      faciales

              

      parotidal

              
       

      Hypopharynx cN+

      Larynx cN+

      Nasopharynx cN+

       

      pyriform sinus

      pharyngeal wall

      esophageal extension

      supraglottic

      glottic

      subglottic

      posterior part

       

      submental (IA)

       

      b

            

      submandibular (IB)

       

      b

           

      b

      ventral jugular sup. (IIA)

      b

      b

      b

      b

      b

      i

      b

      b

      dorsal jugular sup. (IIB)

             

      b

      jugular medial (III)

      b

      b

      b

      b

      b

      b

      b

      b

      jugular inferior (IV)

      b

      b

      b

      b

      b

      b

      b

      b

      cerv. post. prof. (VA)

      b

      b

      b

       

      b

      b

      b

      b

      supraclavicular (VB)

      b

      b

      b

       

      b

      b

      b

      b

      infrahyoidal (VI)

      i

      i

      i

      b

      b

         

      prelaryngeal (VI)

      i

      i

      i

       

      b

      b

        

      pretracheal (VI)

      i

      i

      i

       

      b

      b

        

      paratracheal (VI)

      i

      i

      i

       

      b

      b

      b

       

      retropharyngeal

      b

      b

      b

          

      b

      faciales

             

      b

      parotidal

             

      b

      Table 7

      Suggested guidelines for the treatment of the neck of patients with squamous cell carcinoma in the head and neck region

       

      Ear

      Nasal cavity

      Thyroid gland

       

      external auditory canal

      tympanic cavity

      eustachian tube

      anterior part of mucosa

      posterior part of mucosa

      medial superior part

      lateral superior part

      medial inferior part

      lateral inferior part

      submental (IA)

               

      submandibular (IB)

         

      i

           

      ventral jugular sup. (IIA)

      i

      b

      b

      i

      b

      b

      i

      b

      i

      dorsal jugular sup. (IIB)

               

      jugular medial (III)

      i

      b

      b

      i

      b

      b

      i

      b

      i

      jugular inferior (IV)

           

      b

      i

      b

      i

      cerv. post. prof. (VA)

      i

      b

      b

            

      supraclavicular (VB)

               

      pretracheal (VI)

           

      b

       

      b

       

      paratracheal (VI)

             

      b

       

      thyroidei (VI)

           

      b

      b

      b

      b

      retropharyngeal

       

      b

      b

       

      b

          

      faciales

               

      parotidal

      i

      i

             

      external jugular

               

      retroauricular

               
       

      Orbit

      Parotid gland

      Paranasal sinus

      Cellulae mastoideae

      Submandibular gland

       

      cornea,sclera,lens,retina

      lateral part of conjunctiva

      medial part of conjunctiva

      cranial part

      caudal part

          

      submental (IA)

               

      submandibular (IB)

        

      i

      i

      i

        

      i

       

      ventral jugular sup. (IIA)

       

      i

      i

      i

      i

      b

      b

      i

       

      dorsal jugular sup. (IIB)

         

      i

      i

          

      jugular medial (III)

       

      i

      i

      i

      i

      b

      b

      i

       

      jugular inferior (IV)

         

      i

      i

      i

       

      i

       

      cerv. post. prof. (VA)

         

      i

      i

          

      supraclavicular (VB)

         

      i

      i

          

      pretracheal (VI)

               

      paratracheal (VI)

               

      thyroidei (VI)

               

      retropharyngeal

           

      b

      b

        

      faciales

        

      i

            

      parotidal

       

      i

       

      i

      i

          

      external jugular

          

      i

          

      retroauricular

            

      i

        
      Table 8

      Suggested guidelines for the treatment of the neck of patients with carcinomas of the skin

       

      Skin of scalp

      Skin of neck

      Skin of nose

       

      forehead

      temple

      mastoid region

      parietal part of scalp

      occipital scalp

      nape, side of neck

      ventral part of neck

      supraclavi-cular region

      root of the nose

      other parts

      submental (IA)

                

      submandibular (IB)

      i

              

      i

      ventral jugular sup. (IIA)

      i

      i

      i

      i

      i

      i

       

      i

      i

      i

      dorsal jugular sup. (IIB)

          

      i

           

      jugular medial (III)

      i

      i

      i

      i

      i

      i

      b

      i

      i

      i

      jugular inferior (IV)

           

      i

      b

      i

        

      cerv. post. prof. (VA)

           

      i

          

      supraclavicular (VB)

           

      i

          

      cerv. ant. superf. (VI)

            

      b

         

      pretracheal (VI)

            

      b

         

      paratracheal (VI)

            

      b

         

      faciales

      i

              

      i

      parotidal

      i

      i

            

      i

       

      external jugular

          

      i

           

      retroauricular

        

      i

      i

            

      occipital

          

      i

           
       

      Skin of face

      Skin of ear

       

      lateral eyelid

      medial eyelid

      lacrimal gland, cheek

      lower lip, chin

      upper lip

      anterior part

      lower part

      posterior part

        

      submental (IA)

         

      b

            

      submandibular (IB)

       

      i

      i

      b

      i

           

      ventral jugular sup. (IIA)

      i

      i

      i

      b

      i

      i

      i

      i

        

      dorsal jugular sup. (IIB)

                

      jugular medial (III)

      i

      i

      i

      b

      i

      i

      i

      i

        

      jugular inferior (IV)

            

      i

         

      cerv. post. prof. (VA)

                

      supraclavicular (VB)

                

      cerv. ant. superf. (VI)

                

      pretracheal (VI)

                

      paratracheal (VI)

                

      faciales

       

      i

              

      parotidal

      i

       

      i

        

      i

          

      external jugular

            

      i

         

      retroauricular

             

      i

        

      occipital

                

      Lymph node level

      The main lymph node groups are classified analogically to Som et al. [17] into different levels (Table 4). The level IA contains the submental LN and the level IB the submandibular LN. The LN jugulares ( = LN cervicales laterales profundi) are subdivided in four groups - the LN ventrales jugulares superiores (level IIA), the LN dorsales jugulars superiores (level IIB), LN jugulares mediales (level III) and LN jugulares inferiores (level IV) (Figure 9, 10). We included the retrostyloid space, which range cranial to the scull base, analogically to Som et al. [17] in level IIA. There are only few data available about NM in the retrostyloid space, because a neck dissection do not extend beyond the posterior belly of digastric muscle [7]. Gregoire et al. 2006 [10] recommend to include the retrostyloid space in the CTV for nasopharyngeal cancer or NM in the caudal level II. For N0 patients there are not enough clinical data available to exclude this space from the CTV. The LN level IIB are localised dorsal of the LN level IIA, with the LN level IIA are near to the jugular vein and the LN level IIB are not attached to the jugular vein [17]. The caudal limit of the level IV is set to the clavicle [17]. The level V is divided into the LN cervicales posteriores profundi (level VA) cranial of the musculus omohyoideus and the LN supraclaviculares (level VB) (Figure 8) [18, 19]. The definition of "level V" varies much in the literature. For this reason we decided to follow a definition based on anatomic lymph node regions combined with the surgical and histopathological information, which follows mostly the definition of Rotterdam [1, 3, 4, 9, 20, 21]. The anterior compartment between the both levels III and IV is called level VI and includes the LN cervicales anteriores superficiales and profundi. The main lymph drain flows from level II over level III and IV over the truncus lymphaticus jugularis and/or subclavius to the angulus venosus of the same side of the body (Figure 9, 10) [4]. The truncus can end directly in a vein or on the right side over a ductus lymphaticus dexter or on the left side over the truncus thoracicus. The lymph form level IA flows over level IB to level IIA and the lymph from level VA over level VB to the angulus venosus. Level VI drains to level III and IV. There are still more lymph node regions, which are not respected by the classification by Robbins et al. [19]. The parotidal level contains the LN parotidei superficiales and profundi and drain to level IIA just as well as the level retropharyngeal and level retroauricular, which contains the LN retropharyngeales and LN retroauriculares, respectively. The LN faciales are classified into the level buccales, which drain to the level IB. The level external jugular includes the LN cervicales laterales superficiales and has efflux to the level III.
      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig9_HTML.jpg
      Figure 9

      Schematic scheme of main direction of lymph node flow in the head and neck region.

      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig10_HTML.jpg
      Figure 10

      Coronar DRR with different lymph node regions, bones and veins. The black circle symbolises the angulus venosus.

      General selection and delineation of the lymphatic CTV

      The spread of head and neck tumors into cervical LN is rather consistent and follows predictable pathways, with increasing risk at each level, if the adjoining proximal level is involved [2]. The incidence of occult metastases in LN ranges between 20% and 50% and NM in cN+ (metastatic involvement of LN via clinical assessment) patients ranges between 35% and 80% for all tumors of the oral cavity, pharyngeal and laryngeal tumors, except glottic tumors (0-15% occult metastases). This indicates the necessity to include the adjacent lymph node regions in the CTV.

      Most parts of the head and neck region has rich lymph node vessels. But some sites, as the true vocal cord, the paranasal sinuses and the mediales ear, have only few or no lymphatic vessels at all [7]. Typically the lymph drain remains on one body side. Only some structures, like the soft palate, the base of tongue and the larynx have crossing lymph drain [7]. The retropharyngeal lymph vessel, which involving for example the lymph from the posterior pharyngeal wall and the nasopharynx, often cross the side.

      The lymph drainage from the endolarynx takes different ways (Figure 6, Table 2). The supraglottic endolarynx drains through the membrana thyrohyoidea directly to the LN ventrales jugulares superiores (level IIA) or to the LN infrahyoidei and continuing to the LN jugulares mediales (level III). The lymph from the subglottic endolarynx flows through the ligamentum cricothyroideum to the LN prelaryngeales, LN pretracheales and LN paratracheales and further to the more caudal located LN lower jugulars (level IV). The glottis region of the endolarynx has only few lymph vessels, which are connected mostly to the upper endolarynx, but also to the lower endolarynx [6, 1214].

      The distribution of pathologic confirmed NM depends on three major points - the clinical evaluation of the lymph node sides, the primary tumor side and tumor size [7].

      • Patients with cN+ have a much higher incidence of NM than patients with cN0 (no metastatic involvement of LN via clinical assessment) [22]. Gregoire et al. [7] summarised the results from the Head and Neck Service at Memorial Sloan-Kettering Cancer Center between 1965 and 1989 with 33% metastatic diseases in prophylactic neck dissections and 82% in therapeutic neck dissections. In patients, who underwent therapeutic neck dissection, the pattern of metastatic nodes was similar to the one observed in cN0 patients with one extra level of NM [7].

      • Tumors of different anatomic locations in the head and neck region drain in different percentage to different lymph node level. In cN+ patients Gregoire et al. 2000 described an incidence of metastatic disease in LN is highest in patients with nasopharyngeal cancer (80%) and lowest in patients with tumors of the oral cavity (36%). Patients with a laryngeal cancer have a much higher incidence of NM (54%) in contrast to cancer of the oral cavity, hypopharynx or oropharynx (17-25%), if they have a T3-T4 stage tumor. And more cranial and anterior localised tumors mainly drain into the level I to III in contrast to more caudally located tumors, which mainly drain into level II to V. Nasopharyngeal and oropharyngeal tumors drain not only to the level IIA but also to the level IIB (Table 5, 6). Tumors of the oral cavity, hypopharyngeal and laryngeal tumors are mainly associated to the level IIA and less to the level IIB [7].

      • The incidence of metastatic lymph node involvement increases with the primary tumor size [7, 22, 23].

      • More factors, which influence the lymph node invasion, are the tumor differentiation, kertinization status, lymphatic vessel invasion in the tumor specimen, and whether other lymph node levels are involved [2]. Remmert et al. [22] found for example 16.7% NM for G1 tumors, 36.5% for G2 and 58.9% for G3.

      • If the tumor crosses the midline bilateral treatment of the LN is necessary [24].

      The CTV of the lymph node regions should encompass all regions, who have a probability to contain NM of 10% or more [2, 7]. If the NM infiltrates adjacent structures, the inclusion of this structure and the associated lymph drain in the CTV must individually be assessed [10].

      Summarizing the highest incidence for over all NM can be found in patients with cN+, a laryngeal cancer stage T3/4 and/or nasopharyngeal cancer (cN+). Patients with tumors of the oral cavity (even cN+ or T3/4) have the lowest incidence for NM [7].

      Clinical and pathologic neck node distributions support the concept, that not all lymph node level has to be treated for squamous cell tumors of the head and neck region [7]. All concepts base on retrospective data with possible bias because of mostly selected patients. Some surgery techniques for the neck dissection do not perform lymph node dissection in all level, e.g. level IIb is often not examined, and will result in an underestimation of the involvement of these lymph node levels [7]. Another point is that the incidence of NM in retropharyngeal and paratracheal LN can only be estimated clinically. Medial retropharyngeal LN has been reported to be very rarely involved by radiologic analysis in contrast to the lateral retropharyngeal LN [25, 26]. Therefore it seems to be adequate only to define the lateral retropharyngeal LN as target [27]. To exclude all these problems would require large multicenter randomized trials.

      Both sides of the neck exhibit a similar pattern of node distribution, but with a lower incidence in the contralateral neck. There are only few data on the pattern of contralateral NM.

      This must be assessed by recalculation of relative involvement probabilities to the subregions. The results are still more based on clinical judgment rather than from scientific evidence. Recalculated from the analysis of Gregoire et al. 2000 [7] more than 90% of all NM are found on the ipsilateral side for tumors in the oral cavity or hypopharynx. Tumors of the oropharynx or larynx spread to the contralateral side in 11-14% of the patients. Only for tumors in the nasopharynx over 40% of the contralateral LN show metastases. The relative number of contralateral metastases must be correlated with the absolute number of pathologic LN per bilateral level to find the incidence per neck side. If the tumor invades the midline, the lymph drain to both sides of the neck and therefore both sides should be included in the CTV. Some anatomic regions have crossing lymph node drainage, like the soft palate, the tongue, the larynx and the nasopharynx [12]. But even for those tumors contralateral involvement occurs at a much lower frequency than on the ipsilateral side [7], but should also be included in the CTV (Table 4, 5, 6). As well is the incidence of retropharyngeal LN higher in cN+ patients, in whom involvement of other neck node levels was also documented [7].

      Infiltration of level V is very rare, except level IV is involved or more than a single lymph node in level I-III has metastatic disease (Table 4, 5, 6) [7, 20]. Chone et al. [28] detected NM of level VA in pN0 patients with a prevalence of 2.3% and in pN+ patients with 16.7%. The prevalence was highest for tumors of the pharynx (23.1%) in contrast to tumors of the oral cavity with 3.6%. No NM were found for other tumor sides and there are no isolated metastases in level VA [28].

      Timon at al. [3] found in patients with advanced cancer of the larynx, hypopharynx or cervical esophagus NM in 20% and 43% of the patients, respectively. 10% of the patients had positive paratracheal NM alone in a histopathological negative cervical neck dissection. In subglottic cancer the incidence of paratracheal NM can be up to 50% [7]. Therefore the LN paratracheal should be included in the CTV for patients with advanced laryngeal or hypopharyngeal tumors or extension of the tumor to the cervical esophagus.

      Metastases are labelled as 'skip metastases', if the lymph node involvement bypass a lymph node level and involve the next but one level. Skip metastases are very rare [20]. Remmert et al. [22] analysed 405 patients with head and neck carcinoma and found no skip metastases. A series of the Head and Neck Service at Memorial Sloan-Kettering Cancer Center found skip metastases in 2.5% of the cN0 patients [7, 23]. Only an analysis of tumors of the oral tongue by Byers et al. [29] reached a rate of 12% skip metastases in the level IIb, III and IV.

      Squamous cell cancer of the oral cavity

      The oral cavity itself has primary lymph drainage to the LN submandibulares and submentales (Table 1). Tumors of the tongue drain also directly to level IIA and III [6, 30]. The lymph from the hard palate and upper gingiva flows additionally to the LN retropharyngeales. Squamous cells tumors of the oral cavity have the lowest absolute incidence of NM of all head and neck regions, but the overall incidence of NM for N+ patients is still high with more than 30% [7, 22, 24, 31]. In level IIA, II and III the relative incidence of NM is higher than 10%, independent of the tumor location [6, 7]. These levels should be included in the lymphatic CTV (Table 5). The general probability for contralateral NM is low with < 10% [6]. But the lymph drainage of the tongue has direct significant cross-over with a higher risk of contralateral NM [6, 7, 32]. And the hard palate and upper gingiva have additional lymph drain to the LN retropharyngeales of both sides [7]. Yen et al. [33] found for patients with squamous cell carcinoma of the buccal mucosa a high incidence of NM in the ipsilateral level I to III. Patients with this tumor entity showed only 2% contralateral NM, why it is reasonable only to treat the ipsilateral side [16, 33].

      Robbins et al. [18] has suggested that for N0 patients no elective lymph node dissection of level IIB is necessary [24]. Analogically the level IIB may not be included in the CTV for patients with N0. Byers et al. [29] found a high incidence of NM in level IV in patients with tumors of the (ventral) tongue, which should therefore be included in the CTV, even for N0 patients [24]. Shah et al. [23] described a prevalence of NM in level IV of 3% in patients underwent elective node dissection and 17% in patients with therapeutic neck dissection, wherefore this level should be included in the CTV for all N+ patients of the oral cavity. Oral cavity carcinoma in cN0 patients nearly never metastasizes to level V, which therefore may not be included in the CTV [24]. The incidence for NM in the parotidal LN in patients with oral squamous cell carcinoma is very rare (2.5%) with about 75% intraglandular NM [34].

      Squamous cell cancer of the oropharynx

      The overall incidence of NM is over 60% for squamous cell tumors of the oropharynx [6, 7, 30]. The primary drainage of the tongue base is to level II and III of both sides [6]. An analysis of tumors of the oral tongue by Byers et al. [29] reached a rate of 12% skip metastases in the level IV, for which reason this level should be included in the lymphatic CTV (Table 5). The lymphatic drainage of the tonsil is mainly to level IIA, without crossing the sides [6, 12, 30]. Certainly histopathologic evaluation showed level I (and also level V) involvement only in association with involvement of other levels (N+ disease) [20]. Tumors of the soft palate and dorsal pharyngeal wall show NM on both sides via crossing lymph vessels [6, 7, 12]. For these tumors the retropharyngeal LN should be included in the CTV [7, 35].

      Squamous cell cancer of the hypopharynx

      The lymphatic drain of the piriform sinus is to the LN paratracheales and directly to the level III [6, 12, 30]. The pharyngeal wall has additional efflux to the LN retropharyngeal and the ipsilateral LN prelaryngeales, pretracheales and infrahyoidei. The overall incidence for NM in patients with tumors of the hypopharynx is very high with over 70% [7, 22]. The number of reported detected contralateral NM is low (<10%), but should not be neglected because of the anatomic cross-lymphatic drainage of the hypopharyngeal region [6]. The LN cervicales anteriores profundi (Figure 6, 7), included in level VI, drain lymph not only from the hypopharynx, larynx and thyroid gland, but also from the cervical trachea and upper esophagus [7]. The incidence of pathologic LN in this region is reported rarely. Therefore in the case of tumor infiltration of the cervical trachea or the upper esophagus respectively the level VI should be included in the CTV (Table 6). All hypopharyngeal tumors has a high probability of ipsilateral paratracheal NM, for which reason this region should be included in the CTV [3, 7, 36]. As for patients with tumors of the oral cavity the level IIb must not be included in the CTV for patients with N0 as suggested by Robbins et al. [18]. Histopathologic evaluation showed level I involvement for tumors of the pharyngeal wall in association with involvement of other levels (N+ disease) [20]. The prevalence of level V NM is only in N+ patients high enough to encompass this region in the CTV [20]. For all tumors of the pharyngeal wall the retropharyngeal LN should be included in the CTV [7].

      Squamous cell cancer of the larynx

      The lymphatic drainage of the larynx is different for the supraglottic and subglottic region (Figure 6). The supraglottic endolarynx drains to level IIA, LN infrahyoidei and level II, whereas the subglottic endolarynx drains to level VI (especially LN prelaryngeales, pretracheales, paratracheales) and level IV (Table 6). The glottic region has few lymph vessels, which drain to both regions [6, 1214, 21, 30]. The reported overall incidence for NM varies between 26% and 55% [7, 22]. Especially the supraglottic larynx has a rich lymphatic drainage, resulting in a high incidence of occult cervical metastases [37]. The number of occult NM is about 20% [4, 21]. Even the glottic region has few lymph vessels; the number of NM for advanced tumors adds up to 32% [21]. The number of NM in level II, III and IV is very high for all laryngeal cancers [4, 6, 22, 38]. Especially supraglottic tumors are at risk for crossed lymphatic drainage. The mechanism by which this occurs is still debatable [6]. As for patients with tumors of the larynx the level IIb must not be included in the CTV for patients with N0 as suggested by Robbins et al. [18]. Laryngeal tumors has a high probability of paratracheal NM, especially tumors with subglottic extension, for which reason this region should be included in the CTV [3, 7, 36]. Even for N+ patients the involvement of level I is very rare and can be omitted [7, 38].

      Squamous cell cancer of the nasopharynx

      The lymphatic vessels drain mainly to the LN retropharyngeales, level IIA and VA. Inconsistent channels can drain to the LN parotidales [6, 30]. Squamous cell tumors of the nasopharynx show a very high rate of NM in 80% of the patients [7]. Even for N0 patients the incidence of NM in the bilateral level IIA, IIB, III, IV, VA and VB is high and should be included in the lymphatic CTV (Table 6) [6, 7, 39]. The lymph vessels in the retropharyngeal region are often crossing the sides. Accordingly the number of contralateral NM (30%) is very high in patients with nasopharyngeal cancer [6, 7, 35] and should be included in the lymphatic CTV.

      Other tumors of the head and neck region

      The distribution of cervical NM from primary parotidal carcinoma is rarely reported. Hence there is no consensus as to which extent the cervical level should be irradiated. Chrisholm et al. [40] found in the ipsilateral level I to V more than 20% NM each. Therefore all these level should be encompassed in the CTV (Table 7).

      Squamous cell carcinomas in other location in the head and neck regions are rarely reported and all present analyses bases on small patient groups. Our suggested guidelines contribute mostly on anatomic lymph drain and medical experience. Because of the high overall incidence (<30%) of ipsilateral NM in squamous cell cancer of the maxilla, treatment of the ipsilateral neck should be considered even in cases with a negative clinical examination [41, 42] (Table 7). Patients with auricular squamous cell carcinoma present NM in 10%-30% of the cases [4345]. Clark et al. [44] found, that the parotid gland was the commonest side of node metastases, followed by LN retroauriculares and level II, III and V (Table 7). For the treatment of thyroid carcinoma the level II, II and IV show a high incidence of NM [46].

      Tumors of the skin

      The curative treatment of basal cell carcinoma and squamous cell carcinoma with N0 status mostly includes no treatment of the lymph node regions because of insufficient evidence [47]. For patients with clinical or histological affected lymph nodes the CTV should encompass the lymph node regions listed in Table 8, but at least the affected lymph node region with one additional region. For melanomas the affected lymph node region and two additional regions should be encompassed in the lymphatic CTV. The lymph from the medial eyelid drains to the LN submandibulares and LN faciales, whereas the lymph from the lateral eyelid drains to the LN parotidei profundi and superficiales (Table 8, Figure 11) [12]. The lymph of the upper lip flows to the LN submandibulares and the lymph of the lower lip flows also to the LN submentales with possible crossing of the sides. The anterior parts of the ear drain to the preauriculares, the lower parts to the LN cervicales laterales superficiales and the posterior parts to the retroauriculares LN. The lymph vessels of the forehead and temple run to the LN parotidei superficiales and the lymph vessels of the parietal part of the scalp to the LN retroauriculares. The occipital scalp is drained by the LN occipitales. The dorsal and lateral neck regions have outflow to the LN cervicales posteriors profundi as well as to LN cervicales laterales superficiales. The lymph of the ventral parts of the neck flows to LN cervicales anteriores superficiales and forwards to the LN pre- and paratracheales. The skin of the supraclavicular region drains to LN jugulares.
      http://static-content.springer.com/image/art%3A10.1186%2F1748-717X-6-97/MediaObjects/13014_2011_427_Fig11_HTML.jpg
      Figure 11

      Lymph drain from the skin outlines as a schema on a capital view (for the systematic listing see Table 2): LN preauriculares (yellow, cranial), LN infra-/intraparotidei (light green), LN parotidei superficiales (pink, cranial), LN facials (brown), LN submentales (pink, ventral), LN submandibulares (dark blue), LN retroauriculares (rose), LN cervicales laterales superficiales (cyan cranio-dorsal), LN occipitals (grey), LN cervicales posteriores profundi (yellow, dorsal), LN ventrales jugulares superiores (orange), LN jugulares mediales (dark green), LN jugulares inferiores (cyan, caudo-ventral), LN cervicales anteriores superficiales (yellow, ventral).

      Conclusions

      We have reviewed the expected lymphatic drainage of different parts of the head and neck region and correlated this with the current used level system and histopathologic experience. The results are contoured on various CT slices and summarized in Table 5, 6, 7, 8.

      Declarations

      Acknowledgements

      These guidelines do not intend to give any recommendation for the optimal treatment strategy. Physician will have to weigh available data on patterns of lymph node infiltration for various locations, grad and extent of the primary, organ infiltration, probability of treatment morbidity, extent of NM etc. The review did not analyse the post-operative situation.

      Authors’ Affiliations

      (1)
      Radiotherapy and Radiooncology, University Hospital Göttingen
      (2)
      Radiotherapy and Radiooncology, University Marburg

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