H&N II Nodal Levels & definition of CTV Flashcards
Node negative or node positive
the status of the neck is the single most important prognostic factor in H&N cancer
In order to determine the status of the neck:
- CT or MR imaging is mandatory for staging
-> similar sensitivities, better specificity for CT (sensitivity is the probability of finding a positive result in a patient with the disease, specificity is the probability of finding a negative result in a patient free from the disease)
-> PET/CT has higher sensitivity in:
- distant metastases
- synchronous second primary tumours
- clinically occult primary tumours
Sentinel lymph node biopsy (SLNB)
- identify and remove a nodal level (echelon) using radioscintigraphy and test them for occult disease
- if negative for nodal disease, no further treatment to the neck
- a meta-analysis in 2013 (Thompson et al) showed sentinel node biopsy had sensitivity rates over 90%
- issue: ‘skip’ metastases in the neck (e.g. oral cavity)
AJCC staging system version 8.0
Note that the following does NOT apply* to the N status in nasopharyngeal or oropharyngeal carcinomas
- inclusion of extranodal extension as a prognostic variable
- T status of oral cavity cancer reflects the prognostic value of depth of invasion
- HPV+ve oropharyngeal cancers have been completely restaged
AJCC Version 8 Regional Lymph Nodes
NX
Regional LNs cannot be assessed
AJCC Version 8 Regional Lymph Nodes
N0
No regional LN metastasis
AJCC Version 8 Regional Lymph Nodes
N1
single ipsilateral LN, <=3cm, extranodal extension (ENE) -ve
AJCC Version 8 Regional Lymph Nodes
N2
single ipsilateral LN, <=3cm, ENE +ve
OR >3cm <=6cm, ENE -ve
OR multiple ipsilateral LNs, <6cm, ENE -ve
OR bilateral or contralateral LNs <6cm, ENE -ve
AJCC Version 8 Regional Lymph Nodes
N2a
single ipsilateral or contralateral <=3cm, ENE+ve
OR
single ipsilateral LN >3cm <=6cm, ENE-ve
AJCC Version 8 Regional Lymph Nodes
N2b
multiple ipsilateral LNs, <6cm, ENE-ve
AJCC Version 8 Regional Lymph Nodes
N2c
bilateral or contralateral LNs, <6cms, ENE-ve
AJCC Version 8 Regional Lymph Nodes
N3
single LN >6cm, ENE-ve OR
single ipsilateral LN >3cm, ENE+ve OR
multiple ipsi, contra or bilateral LNs, with any EVE+ve
AJCC Version 8 Regional Lymph Nodes
N3a
Metastasis single LN >6cm, ENE-ve
AJCC Version 8 Regional Lymph Nodes
N3b
single ipsilateral >3cm, ENE+ve OR
multiple ipsi, contra or bilateral LNs, with any ENE+ve
Node negative or positive?
- if the neck is deemed nose negative (N0), treatment of the neck nodes is elective. Observation (with regular U/S) is also an option (typically 2 dose levels)
- if the neck is deemed node positive (N1+), treatment of the neck nodes is therapeutic (typically 3 dose levels)
options for management of neck
- options are surgical neck dissection or RT
- the selection of surgery or RT for neck management is determined by the treatment option to the primary site (if surgery is primary treatment, surgery is neck management / if chemoRT is primary treatment, RT for neck management)
- elective neck irradiation is as effective as elective neck dissection - local control rates around 90%
- if the primary tumour is to be treated with RT, the first echelon lymph nodes are contained in the primary PTV and receive full dose (also refer to these as grossly involved lymph nodes. Gross lymph nodes (first echelon) must receive full dose. They go into GTV)
- if bilateral neck is to be treated, bilateral irradiation is preferable to bilateral neck dissection (less morbidity)
Types of neck dissection
There are 3 categories and 6 types of neck dissection:
1. Selective neck dissection (SND)
2. Comprehensive or therapeutic neck dissection consisting of:
1. radical neck dissection (RND) or
2. modified radical neck dissection (MRND) Types I-III
3. Extended neck dissection
Selective Neck dissection
- selective neck dissection (SND) is conducted in the N0 neck or for very limited cervical metastases
- in a SND, there is preservation of one or more lymph node levels
Radical Neck Dissection
Radical neck dissection involved the surgical removal of Levels I-V and includes resection of sternocleidomastoid muscle (SCM) and accessory nerve (XIn) and internal jugular vein (IJV)
Modified Radical Neck Dissection
Modified radical neck dissection removes level I-V nodes but preserves SCM and/or XIn and/or IJV
MND type I dissection preserves 1 of the 3 structures above, usually XIn (accessory nerve)
MND type II preserves 2 of the 3 structures usually XIn and IJV (most common procedure)
MND type III preserved all 3 structures. (levels I-V dissected)
Completed MRND Type II
steps involved
- opening of neck
- dissection of level IB
- identification of XIIn and IJV
- identification of XIn
- identification of omohyoid and SCM
- raising of skin flap
- dissection out of XIn
- dissection out level IIB
- division of clavicular and sternal heads of SCM
- freeing inferolateral aspect of level V
- dissection of levels II-V
- deliver specimen
extended neck dissection
extended neck dissection includes removal of one or more additional lymphatic groups (e.g. level VII) or non-lymphatic structures (skin, muscle, nerve, blood vessels) not usually included in a comprehensive neck dissection.
Management of node positive neck
N1 neck
similar to elective management of the N0 neck, the management of the N+ neck is determined by the treatment to the primary tumour.
- single ipsilateral LN, <=3cm, ENE -ve
- single modality treatment is sufficient. If treatment is surgical, SND may be appropriate
- note that many (up to 50%) of necks are upstaged post surgery and pathology and may then require post-op RT
Management of node positive neck
N2 neck
- single ipsilateral LN, ENE +ve OR >3cm <=6cm, ENE-ve OR
- multiple ipsilateral LNs, <6cm, ENE-ve OR
- bilateral or contralateral LNs <6cm, ENE-ve
Management of node positive neck
N3 neck
- single LN >6cm, ENE-ve OR
- single ipsilateral LN >3cm, ENE+ve OR
- multiple ipsi, contra or bilateral LNs, with any ECE+ve
N2 + N3 neck
surgical management
- if treatment to primary is surgical, then modified radical neck dissection and radical neck dissection have equal results in appropriately selected patients
- SQ: for those with unfavourable features (extracapsular nodal spread, positive margins, pT3 or pT4 primary, nodal disease in levels IV or V, perineural invasion, vascular invasion), post-op RT increases locoregional control
- Note: morbidity associated with post-op RT following RND is significant
N2 + N3 neck
RT management
- for N2 neck and above, chemoradiation is required
- 10-12 weeks post chemoradiation, PET/CT is acquired
-> complete response –> no further treatment
-> incomplete or equivocal response –> salvage neck dissection
(at salvage, selective neck dissection is most favourable for morbidity reasons)
Nodal level definition
Level Ia
- Nodes:
submental nodes - Areas drained:
1. skin of chin
2. mid-lower lip
3. tip of tongue
4. anterior floor of mouth - H&N site:
1. floor of mouth (FOM)
2. anterior oral tongue
3. anterior mandibular alveolar ridge
4. lower lip (skin cancer, SCC of lip)
Nodal level definition
Level Ib
- Nodes:
submandibular - Areas drained:
1. efferent lymphatics from Ia
2. lower nasal cavity
3. hard and soft palate
4. maxillary and mandibular alveolar ridge
5. cheek, upper and lower lips
6. anterior tongue - H&N site
1. oral cavity
2. anterior nasal cavity
3. soft tissues of mid-face (sinus / paranasal sinus tumour that has come through the skin)
4. submandibular gland
Nodal level definition
Level II
- Nodes:
upper jugular nodes - Areas drained:
1. efferent lymphatics from face, parotid gland, submandibular gland, submental gland and retropharyngeal nodes
2. nasal cavity
3. pharynx
4. larynx
5. external auditory canal
6. middle ear
7. SM and sublingual glands - H&N site:
1. nasal cavity
2. soft tissues of mid-face
3. submandibular gland
Nodal level definition
Level III
- Nodes:
middle jugular nodes - Areas drained:
1. efferent lymphatics from levels II and V
2. efferent lymphatics from RP, pre-tracheal and recurrent laryngeal lymphatics
3. base of tongue (BOT)
4. tonsils
5. larynx
6. hypopharynx
7. thyroid - H&N site:
1. oral cavity
2. nasopharynx
3. hypopharynx
5. larynx
Nodal level definition
Level IVa
- Nodes:
lower jugular nodes - Areas drained:
1. efferent lymphatics from levels III and V
2. some efferent lymphatics from RP, pre-tracheal and recurrent laryngeal nodes
3. lymphatics from hypopharynx, larynx, thyroid - H&N site:
1. hypopharynx
2. larynx
3. thyroid
4. cervical oesophagus
Nodal level definition
Level IVb
- Nodes:
medial supraclavicular nodes - Areas drained:
1. efferent lymphatics from levels IVa and Vc
2. some efferent lymphatics from pre-tracheal and recurrent laryngeal nodes
3. lymphatics from hypopharynx, larynx, thyroid, trachea and oesophagus - H&N site:
1. hypopharynx
2. subglottic larynx
3. thyroid
4. cervical oesophagus
5. trachea
Nodal level definition
Level Va, Vb
Levels Va and Vb (surgical viewpoint to separate them using caudal edge of cricoid cartilage as landmark)
- Nodes:
Posterior triangle nodes
- Areas drained:
1. efferent lymphatics from occipital and retroauricular nodes
2. some efferent lymphatics occipital and parietal scalp
3. skin of lateral and posterior neck and shoulder
4. nasopharynx
5. oropharynx
6. thyroid gland
- H&N site:
1. nasopharynx
2. oropharynx
3. thyroid
4. cutaneous structures of posterior scalp (skin cancer of scalp)
Nodal level definition
Level Vc
- Nodes:
lateral supraclavicular nodes - Areas drained:
1. efferent lymphatics from levels Va and Vb - H&N site:
1. nasopharynx
Nodal level definition
Level VIa, VIb
- Nodes:
anterior compartment nodes consisting of: anterior jugular nodes (VIa), pre-laryngeal, pre-tracheal, recurrent laryngeal nodes (VIb) - Areas drained:
1. efferent lymphatics from anterior floor of mouth, tip of tongue, lower lip, thyroid, glottis, supraglottis, hypopharynx, cervical oesophagus - H&N site:
1. lower lip (skin cancer)
2. oral cavity (FOM and tip of tongue)
3. thyroid
4. glottis
5. supraglottis
6. apex of piriform sinus
7. cervical oesophagus
Nodal level definition
Level VIIa
- Nodes:
RP nodes - Areas drained:
1. efferent lymphatics from mucosa of nasopharynx, Eustachian tube, soft palate - H&N site:
1. nasopharynx
2. posterior pharyngeal wall
3. oropharynx
Nodal level definition
Level VIIb
- Nodes:
retro-styloid nodes - Areas drained:
1. efferent lymphatics from mucosa of nasopharynx - H&N site:
1. nasopharynx
2. any other H&N cancer primary with massive/bulk infiltration of level II nodes (as level VIIb is anatomically the cranial continuation of level II)
Nodal level definition
Level VIII
- Nodes:
parotid node group: subcutaneous pre-auricular nodes, superficial and deep intraparotid nodes and subparotid nodes - Areas drained:
1. efferent lymphatics from frontal and temporal skin, eyelids, conjunctiva, EAM, nasal cavities, nasopharynx, Eustachian tube, pinna - H&N site:
1. tumours of frontal and temporal skin
2. orbit
3. external auditory canal
4. nasal cavities
5. parotid gland
Nodal level definition
Level IX
- Nodes:
malar and bucco-facial node group: superficial lymph nodes around facial vessels on external surface of buccinator (inconsistent) - Areas drained:
1. efferent lymphatics from nose, eyelids, cheek - H&N site:
1. tumours of skin of face
2. tumours of skin of nose
3. maxillary sinus infiltrating soft tissue of cheek
4. buccal mucosa
Nodal level definition
Level Xa
- Nodes:
retro-auricular nodes and sub-auricular nodes - Areas drained:
1. efferent lymphatics from posterior surface of the pinna, external auditory canal (EAC), scalp adjacent to EAC - H&N site:
1. skin cancers of retro-auricular area
Nodal level definition
Level Xb
- Nodes:
occipital nodes - Areas drained:
1. efferent lymphatics from posterior scalp - H&N site:
1. skin cancers of occipital area
Definition of the GTV primary
- clinical examination of pharynx and oral cavity
- pharyngo-laryngeal fibreoptic examination with written description of tumour extension and infiltration
- direct endoscopy under examination under anaesthetics by ENT specialist with photos/drawings (may not be necessary for oral cavity lesions) and biopsy
- diagnostic contrast-enhanced CT and/or MRI (MRI for oral cavity and oropharynx and CT for larynx and hypopharynx). Can also fuse these. PET recommended only for locally advanced tumours.
Definition of CTV-P
‘5+5mm expansion’ from GTV-P rationale
- started with the DAHANCA experience
- surgical series (x3) indicates that microscopic tumour infiltration nearly always occurs within a distance of 0-10mm from the edge of the GTV-P.
-> recognised that it does not cover 100% of all tumours but has to be balanced with toxicity likelihood
-> there are two elements to CTV-P: CTV-P1 is GTV-P expanded by 5mm and CTV-P2 is GTV-P expanded by 10mm
Editing of CTV-P
CTV-P is not just a 3D geometric expansion of GTV-P. Must consider anatomic patient features:
- air cavities must be edited out because of the dose distribution
- complex anatomy - abutting contiguous mucosal surfaces
- natural H&N anatomic barriers such as bone
- lessons learned for specific subsites based on surgical series e.g. T1 glottis, T1 tonsil
Dose levels - IMRT SIB Technique
- prescription for H&N cancer RT
- can be either 2 dose levels or 3 dose levels
- if 2 dose levels:
-> CTV-P1 will be the target dose - dose equivalent of 70Gy in 2Gy fractions
-> CTV-P2 will be the prophylactic dose - dose equivalent of 50Gy in 2Gy fractions - if 3 levels of dose prescription, the CTV-P2 is an intermediate dose level: dose equivalent of 60Gy in 2Gy fractions and CTV-P3 is delineated and given a prophylactic dose level-dose equivalent of 50Gy in 2Gy per fraction.
