L37 - Cancer of ENT, Head & Neck Region Anatomic & Physiologic appraisal

Question 1

List localized and systemic treatment options for Head and neck cancers?

Answer 1

Localized:

1. Surgery:
   - Radical excision
   - Reconstruction (use prosthetic)
2. Radiotherapy

Systemic:

1. Chemotherapy (usually adjuvant)
2. Immunotherapy (boost system to fight cancer) Usually combine modalities

Question 2

Why does ‘form’ matter in treatment of head and neck cancers?

Answer 2

Head and neck region usually not covered: treatment can affect:

• External appearance
• Patient’s psychosocial well-being

Question 3

Why does ‘function’ matter in treatment of head and neck cancers?

Answer 3

Treatment must aim to preserve as much function as possible:

 Vital sensory functions: hearing, vision, smell, taste

 Breathing

 Swallowing

 Speech

 Facial expression

Question 4

Explain how NPC leads to hearing loss and tinnitus?

Answer 4

(NPC) can obstruct the Eustachian tube opening

>> cause fluid to accumulate in the middle ear

>> conductive deafness, including unilateral hearing loss and unilateral tinnitus

Question 5

What are some considerations on ‘form and function’ if ear cancer at different segments is treated?

Answer 5

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)

Question 6

List 2 Bones of skull base that separate intracranial structures from nasal cavity

Answer 6

Lamina papyracea

Cribriform plate

Question 7

List 2 intra-cranial bones that can be invaded by nasal cavity cancer?

Answer 7

Lamina papyracea

Cribriform plate

Question 8

Consequences of nasal cancer spreading though lamina papyracea?

Answer 8

• 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

Question 9

Consequences of nasal cancer spreading though cribiform plate?

Answer 9

olfactory nerve passes through plate = passage for cancer to invade the brain

Cause damage to frontal area, causing mood changes with late presentation

Question 10

Give one early symptoms of paranasal sinus cancer?

Answer 10

blood-stained nasal discharge

Hidden, Makes cancer difficult to detect

Question 11

List the paranasal sinuses?

Answer 11

frontal, ethmoid, maxillary, sphenoid

Question 12

List 2 modalities of treating advanced tongue cancer + outcome of treatment?

Answer 12

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

Question 13

List 3 benign lesions in the neck?

Answer 13

cysts, neurofibroma, haemangioma

Question 14

Internal and external structures that bound deep lymphatics of the neck? *exam*

Answer 14

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

Question 15

Describe the pattern of lymphatic spread of head and neck cancer?

Answer 15

spread to neck lymph nodes in a predictable pattern

Cancers from different location spread to different levels first

Skip metastasis is uncommon

Question 16

How much tissue should be removed if a head and neck cancer has lymphatic spread?

Answer 16

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

Question 17

How are neck lymph nodes divided?

Answer 17

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

Question 18

Define level 1 neck lymph node location.

Answer 18

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

Question 19

Define the regions drained by level 1 neck lymph nodes?

Answer 19

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

Question 20

Define the location of level II neck lymph nodes? List the structures drained at this level. (8)

Answer 20

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

Question 21

Why is Level IIb neck lymph nodes important head and neck pathologies?

Answer 21

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

Question 22

Define the location of level III neck lymph nodes? List the structures drained at this level. (4)

Answer 22

Hyoid to cricoid

 Oral cavity  Oropharynx  Larynx  Hypopharynx

Question 23

Define the location of level IV neck lymph nodes? List the structures drained at this level. (4)

Answer 23

Cricoid to clavicle

 Hypopharynx  Larynx  Thyroid  Cervical oesophagus

Question 24

Level IV neck lymph nodes are common for submandibular tumours to spread to. T or F?

Answer 24

Uncommon for submandibular tumor to spread here, except 10-15% base of tongue cancer

Question 25

Define the location of level V neck lymph nodes? List the structures drained at this level.

Answer 25

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

Question 26

Which level of neck lymph nodes commonly conducts NPC spread?

Answer 26

Level V: posterior triangle

Question 27

Which neck lymph node resides in the Supraclavicular fossa? Structures drained?

Answer 27

lowest nodes in levels IV + V

Drainage from neck above or below the clavicle

Question 28

Compare the lesions between L and R supraclavicular fossa and cancers that can spread there?

Answer 28

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

Question 29

List the treatment options if diffuse neck lymph nodes are involved in cancer spread?

Answer 29

1) Radical neck dissection
2) Modified radical neck dissection
3) Selective neck dissection

Question 30

Compare the structures removed between radical neck dissection and Modified radical neck dissection?

Answer 30

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

Question 31

Why is modified radical neck dissection better than radical neck dissection?

Answer 31

improve functional outcome without jeopardizing control of nodal disease

Question 32

Vagus and segments of internal carotid artery are removed during radical neck dissection. T or F?

Answer 32

False

cannot remove vagus nerve, internal carotid artery

Question 33

Indication of selective neck dissection? How much tissue is removed?

Answer 33

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

Question 34

Select the neck dissection modality of treatment for oral tongue cancer?

Answer 34

Selective neck dissection: Supraomohyoid neck dissection (I,II,III)

Question 35

Select the neck dissection modality of treatment for thyroid cancer?

Answer 35

Selective neck dissection: Central compartment dissection (bilateral level VI; or unilateral to maintain blood supply and prevent hypothyroidism)

Question 36

List 2 ways to detect physiological abnormalities in thyroid/ parathyroid cancers?

Answer 36

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

Question 37

Structures in close proximity to thyroid that be preserved in treatment of thyroid cancers?

Answer 37

Recurrent laryngeal nerve (RLN)

Superior laryngeal nerve (SLN)

Trachea

Question 38

List all the structures supplied by the recurrent laryngeal nerve?

Answer 38

Recall = branch of CN X, supplies:

 Cricopharyngeus

 Infraglottic area (sensory below vocal folds)

 All intrinsic muscles of larynx except cricothyroid

Question 39

Explain how thyroid cancer/ goitre can cause hoarseness of voice?

Answer 39

Compression of recurrent laryngeal nerve, affect nerve supply to laryngeal muscles >> hoarseness

Question 40

Distinguish the sequalae of unilateral vs bilateral recurrent laryngeal nerve damage?

Answer 40

Unilateral RLN injury: Hoarseness + choking

Bilateral RLN injury: Bilateral vocal cord palsy (recall posterior cricoarytenoid muscle) = airway obstruction

Question 41

List all the structures supplied by the superior laryngeal nerve?

Answer 41

branch of CN X:

• External branch >> cricothyroid muscles
• Internal branch supplies sensory above vocal folds (vestibule)

Question 42

Explain why upper thyroidetomy causes inability to sing high pitch? *exam*

Answer 42

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

Question 43

Choose a treatment modality for small** cancer of right hypopharynx ?

Answer 43

Local excision feasible

Vocal cord spared = good voice

Question 44

Choose a treatment modality for right hypopharynx cancer paralysing the right vocal cord? Treatment outcome?

Answer 44

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

Question 45

Give one example of skin flap after radical neck dissection?

Answer 45

Fasciocutaneous flaps – e.g. deltopectoral flap >> Skin coverage for neck defect

Question 46

Give one example of mandibular reconstruction surgery?

Answer 46

Fibula free flap (not essential for weight-bearing = can still walk)

Hook up peroneal vessel to vessels in neck (microvascular anastomosis)