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
