L37 - Cancer of ENT, Head & Neck Region Anatomic & Physiologic appraisal Flashcards
List localized and systemic treatment options for Head and neck cancers?
Localized:
- Surgery:
- Radical excision
- Reconstruction (use prosthetic) - Radiotherapy
Systemic:
- Chemotherapy (usually adjuvant)
- Immunotherapy (boost system to fight cancer) Usually combine modalities
Why does ‘form’ matter in treatment of head and neck cancers?
Head and neck region usually not covered: treatment can affect:
- External appearance
- Patient’s psychosocial well-being
Why does ‘function’ matter in treatment of head and neck cancers?
Treatment must aim to preserve as much function as possible:
Vital sensory functions: hearing, vision, smell, taste
Breathing
Swallowing
Speech
Facial expression
Explain how NPC leads to hearing loss and tinnitus?
(NPC) can obstruct the Eustachian tube opening
>> cause fluid to accumulate in the middle ear
>> conductive deafness, including unilateral hearing loss and unilateral tinnitus
What are some considerations on ‘form and function’ if ear cancer at different segments is treated?
External ear (auricle): Radical Removal = cosmetic problem, impact psychosocial health (form)
Inner ear: Cochlea: Radiation therapy nearby can cause damage to cochlea, cause progressive hearing loss (function)
List 2 Bones of skull base that separate intracranial structures from nasal cavity
Lamina papyracea
Cribriform plate
List 2 intra-cranial bones that can be invaded by nasal cavity cancer?
Lamina papyracea
Cribriform plate
Consequences of nasal cancer spreading though lamina papyracea?
- thinnest bone in body - cancer can easily spread to orbital content >> may need to remove eye for tumour clearance
- If medial rectus is paralyzed>> cannot adduct eye and cause diplopia
Consequences of nasal cancer spreading though cribiform plate?
olfactory nerve passes through plate = passage for cancer to invade the brain
Cause damage to frontal area, causing mood changes with late presentation
Give one early symptoms of paranasal sinus cancer?
blood-stained nasal discharge
Hidden, Makes cancer difficult to detect
List the paranasal sinuses?
frontal, ethmoid, maxillary, sphenoid
List 2 modalities of treating advanced tongue cancer + outcome of treatment?
1) Radical removal of tongue = affects speech (articulation), swallowing (cannot push bolus to pharynx)
2) Reconstruction of tongue: - Only provides lining (skin, fascia) - No muscular function - Functional results depends on residual tongue muscles
List 3 benign lesions in the neck?
cysts, neurofibroma, haemangioma
Internal and external structures that bound deep lymphatics of the neck? *exam*
Deep lymphatics lie in the fascia spaces bound by:
- Investing fascia (externally)
- Prevertebral,carotid, pretracheal fascia (internally)
- Lymphatics do not run within the carotid sheath / fascial wrappings of the neck
Describe the pattern of lymphatic spread of head and neck cancer?
spread to neck lymph nodes in a predictable pattern
Cancers from different location spread to different levels first
Skip metastasis is uncommon
How much tissue should be removed if a head and neck cancer has lymphatic spread?
Lymph nodes may be in close association with the fascia
>> extracapsular spread into surround fascia is common
>> remove the structures wrapped by fascia for tumour clearance
e.g. Sternocleidomastoid (SCM), Internal jugular vein (IJV) …etc
How are neck lymph nodes divided?
6 levels:
Level I – submental and submandibular
Level II – upper jugular
Level III – mid jugular
Level IV – lower jugular
Level V – posterior triangle
Level VI – pretracheal SCF – lowest nodes in level IV and V
Define level 1 neck lymph node location.
submental, submandibular region:
Separated into 1a and 1b:
Ia (submental): anterior to anterior belly of digastric
Ib (submandibular): between anterior and posterior belly of digastric
Define the regions drained by level 1 neck lymph nodes?
1a = submental: - Anterior floor of mouth, - Mandibular incisors, - Tongue tip, - Lower lip
1b = submandibular: - Oral cavity (lateral/ buccal) - Oral tongue, - Anterior nasal cavity, - Submandibular gland
Define the location of level II neck lymph nodes? List the structures drained at this level. (8)
Mastoid to hyoid, under SCM
Above accessory nerve = IIb
Below accessory nerve = IIa
- Nasal cavity and sinuses - Oral cavity - Oropharynx - Nasopharynx - Supraglottic larynx - Hypopharynx - Parotid and submandibular glands
Why is Level IIb neck lymph nodes important head and neck pathologies?
IIb carries jugulodiagastric LN
below the posterior belly of the digastric muscle and anterior to the internal jugular vein
which drains almost all of head except inferior neck
Define the location of level III neck lymph nodes? List the structures drained at this level. (4)
Hyoid to cricoid
Oral cavity Oropharynx Larynx Hypopharynx
Define the location of level IV neck lymph nodes? List the structures drained at this level. (4)
Cricoid to clavicle
Hypopharynx Larynx Thyroid Cervical oesophagus
Level IV neck lymph nodes are common for submandibular tumours to spread to. T or F?
Uncommon for submandibular tumor to spread here, except 10-15% base of tongue cancer
Define the location of level V neck lymph nodes? List the structures drained at this level.
posterior triangle: bound anteriorly by the posterior border of SCM, and posteriorly by the anterior border of the trapezius muscle
Va = above cricoid
Vb = below cricoid
Nasopharynx (commonest for NPC to spread here) Oropharynx Posterior neck and scalp
Which level of neck lymph nodes commonly conducts NPC spread?
Level V: posterior triangle
Which neck lymph node resides in the Supraclavicular fossa? Structures drained?
lowest nodes in levels IV + V
Drainage from neck above or below the clavicle
Compare the lesions between L and R supraclavicular fossa and cancers that can spread there?
Right side – Infra-clavicular lesion: primary tumour from larynx, thyroid, lungs
Left side – infra-clavicular lesion or infradiaphragmatic lesions (via thoracic duct): primary tumour from almost all of body
List the treatment options if diffuse neck lymph nodes are involved in cancer spread?
1) Radical neck dissection
2) Modified radical neck dissection
3) Selective neck dissection
Compare the structures removed between radical neck dissection and Modified radical neck dissection?
Radical:
- Level I-V lymphatics
- Sternocleidomastoid muscle
- Internal jugular vein
- Accessory nerve (CN XI) (pass through lymphatic layer)
- Cervical plexus
Modified radical: Preserve >=1 of the following:
- Sternocledomastoid muscle
- Internal jugular vein
- Accessory nerve
Remove: - Level I-V lymphatics - Cervical plexus
Why is modified radical neck dissection better than radical neck dissection?
improve functional outcome without jeopardizing control of nodal disease
Vagus and segments of internal carotid artery are removed during radical neck dissection. T or F?
False
cannot remove vagus nerve, internal carotid artery
Indication of selective neck dissection? How much tissue is removed?
For patients with no clinical evidence of nodal metastasis but the cancer has high chance of occult nodal metastasis
Removal of certain areas of lymphatics that has the highest chance of occult nodal metastasis
Select the neck dissection modality of treatment for oral tongue cancer?
Selective neck dissection: Supraomohyoid neck dissection (I,II,III)
Select the neck dissection modality of treatment for thyroid cancer?
Selective neck dissection: Central compartment dissection (bilateral level VI; or unilateral to maintain blood supply and prevent hypothyroidism)
List 2 ways to detect physiological abnormalities in thyroid/ parathyroid cancers?
Solidary adenoma cause hyperthyroidism >> Secrete thyroxine independent of TSH >> take up more iodine isotope (= hot nodule)
Parathyroid adenoma cause hypercalcemia >> Tc-99m-MIBI scan to identify which of the 4 parathyroid affected
Structures in close proximity to thyroid that be preserved in treatment of thyroid cancers?
Recurrent laryngeal nerve (RLN)
Superior laryngeal nerve (SLN)
Trachea
List all the structures supplied by the recurrent laryngeal nerve?
Recall = branch of CN X, supplies:
Cricopharyngeus
Infraglottic area (sensory below vocal folds)
All intrinsic muscles of larynx except cricothyroid
Explain how thyroid cancer/ goitre can cause hoarseness of voice?
Compression of recurrent laryngeal nerve, affect nerve supply to laryngeal muscles >> hoarseness
Distinguish the sequalae of unilateral vs bilateral recurrent laryngeal nerve damage?
Unilateral RLN injury: Hoarseness + choking
Bilateral RLN injury: Bilateral vocal cord palsy (recall posterior cricoarytenoid muscle) = airway obstruction
List all the structures supplied by the superior laryngeal nerve?
branch of CN X:
- External branch >> cricothyroid muscles
- Internal branch supplies sensory above vocal folds (vestibule)
Explain why upper thyroidetomy causes inability to sing high pitch? *exam*
Injury to superior laryngeal nerve during dissection of upper pole of thyroid / thyroidectomy
External SLN branch injury = cricoarytenoid cannot lengthen vocal cord = unable to sing high pitch
Choose a treatment modality for small** cancer of right hypopharynx ?
Local excision feasible
Vocal cord spared = good voice
Choose a treatment modality for right hypopharynx cancer paralysing the right vocal cord? Treatment outcome?
Invaded right cord =cannot swallow, breathe
Options:
1) Total laryngectomy >> Loss of speech, Loss filter function of the nose, Loss of humidification (more sputum), Ineffective cough (cannot close glottis for +ve pressure)
2) Alternative: chemotherapy + radiotherapy
Give one example of skin flap after radical neck dissection?
Fasciocutaneous flaps – e.g. deltopectoral flap >> Skin coverage for neck defect
Give one example of mandibular reconstruction surgery?
Fibula free flap (not essential for weight-bearing = can still walk)
Hook up peroneal vessel to vessels in neck (microvascular anastomosis)
