HNS37 Common ENT Cancers: Anatomic And Physiologic Appraisal Flashcards
Treatment of head and neck cancer
- Surgery
- Radical excision
- Reconstruction - Radiotherapy
- Chemotherapy (usually adjuvant)
- Combined modality
NB: Treatment can affect external appearance (form) unlike other regions (GI surgery)
—> affects psychosocial well being
Function of head and neck
- Vital sensory functions
- heading, vision, smell, taste - Breathing
- Swallowing
- Speech
- Facial expression
Ear structure
- External
- Middle ear
- Ear drum
- Ossicles - Inner ear
- Cochlea
- Semicircular canals
—> Hearing and Balance
Nasopharyngeal cancer and Ear
Nasopharyngeal cancer
—> Obstruct Eustachian tube opening
—> Fluid to accumulate in middle ear
—> Conductive deafness
Symptoms of NPC
- Unilateral hearing loss
- Unilateral tinnitis
Ear and treatment
- Removal of external ear —> cosmetic problem
2. Radiation therapy near inner ear can cause damage to cochlear and progressive hearing loss
Nose structure
- Nasal cavity
- Paranasal sinuses
- frontal, maxillary, ethmoid, sphenoid - Eustachian tube
- connecting middle ear and nasopharynx
—> Smell and Air passage
***Nose cancers
- Sinuses
- deep in skull
- hidden
- cancer difficult to detect (although rare)
- early symptom: blood stained nasal discharge - Lamina papyracea (thinnest bone in body in ethmoid sinus)
—> cancer can easily spread to ***orbital content
—> Medial rectus affected (affect vision) / Proptosis
—> may need to remove eye for tumour clearance - Bones of skull base (e.g. anterior cranial fossa)
- separates intracranial structures from nasal cavity - Cribriform plate
- olfactory nerve passing through
- passage for cancer to invade the brain
Oral cavity, Oropharynx structure
- Lip, tongue, mandible, teeth, palate, floor of mouth, buccal mucosa
- Salivary glands
- Tonsils, posterior pharyngeal wall
—> Food passage and Defence
—> Taste and Speech
Oral cavity, Oropharynx treatment
- Removal of tongue
—> affects speech and swallowing
—> <=1/2 removed —> usually ok - Reconstruction of tongue
—> only provides lining
—> no muscular function
Functional results depends on residual tongue muscles
Neck pathologies
- Benign lesion in neck
- Cysts
- Neurofibroma (tumour grow within nervous system)
- Haemangioma (benign tumour of blood vessels) - Lymph nodes
- neck dissection
- cancer spreading - Important structures
- cranial nerves, arteries, veins
Lymphatic drainage of neck
Lymphatics: does NOT run within Carotid sheath / Fascial wrappings of neck
Deep lymphatics:
- lies in fascia spaces bound by:
—> Deep investing fascia externally
—> Prevertebral, Carotid, Pretracheal fascia internally
***6 levels of neck LNs
Level 1: Submental (A) and Submandibular (B)
Level 2: Upper jugular (divided by CN11 into A + B) (2A: ***Jugulodigastric LN: combined drainage of all upper head and neck)
Level 3: Mid jugular (hyoid to cricoid)
Level 4: Lower jugular (cricoid to clavicle)
Level 5: Posterior triangle (behind SCM, A + B)
Level 6: Pretracheal
Supraclavicular fossa LN: lowest nodes in level 4 and 5
Metastatic neck lymph nodes
LNs may be in close association with fascia
—> cancer spread in LN
—> may ***spread into fascia
—> may need remove structures wrapped by fascia for tumour clearance
Structures can be sacrificed:
- SCM
- ECA
- IJV
- CN11
Structures cannot be sacrificed:
- Internal / Common carotid artery (in Carotid sheath)
- CN10 (swallowing) (in Carotid sheath)
- Phrenic nerve (breathing)
- Brachial plexus (arm function) (in Posterior triangle)
Pattern of LN spread in head and neck cancer
Head and Neck cancer may spread to Neck LN
- Predictable pattern
- Skip metastasis uncommon
Cancers from different location spread to different levels first
LN metastasis origin of different levels
由邊個structure入去個LN到
Level 1a (Submental):
- ***lower lip
- ***anterior floor or mouth
- mandibular incisors
- tongue tip
Level 1b (submandibular):
- lateral oral cavity (buccal)
- oral tongue
- ***anterior nasal cavity
- ***submandibular gland
Level 2 (Upper jugular): Everywhere (∵ Jugulodigastric LN: combined drainage of all upper head and neck) - nasal cavity and sinuses - oral cavity - oropharynx - nasopharynx - supraglottic larynx - hypopharynx - parotid and submandibular - upper thyroid gland
Level 3 (Mid jugular):
- oral cavity
- ***oropharynx
- ***larynx
- hypopharynx
Level 4 (Lower jugular):
- hypopharynx
- ***larynx
- ***thyroid
- cervical esophagus
Level 5 (Posterior triangle (behind SCM, A + B)):
- ***nasopharynx
- ***oropharynx
- ***posterior neck and scalp
Supraclavicular fossa LN: lowest nodes in level 4 and 5:
- drainage from neck above / below clavicle
- right side: infra-clavicular lesion
- left side: infra-clavicular lesion / **infra-diaphragmatic lesion (via thoracic duct) —> **Virchow’s node (∵ lower body drains through left side)
Neck dissection
Removal of lymphatics in the neck that harbours cancer metastasis
***Radical neck dissection: Removal of - Level 1-5 LN (ipsilateral) - SCM - IJV - CN11 (pass through lymphatic layer) - Cervical plexus (pass through lymphatic layer) (functional deficit but acceptable)
***Modified radical neck dissection:
Modification of radical neck dissection by preserving:
- SCM
- IJV
- CN11
—> Aim: improving functional outcome without jeopardising control of nodal disease
***Selective neck dissection:
Removal of certain areas of LN that has highest chance of occult nodal metastasis
- Oral tongue cancer —> Supraomohyoid neck dissection (Level 1-3) for oral tongue cancer
- Tonsil cancer —> Level 2-4
- Thyroid cancer —> Central compartment dissection (bilateral level 6)
—> usually reserved for patients with no clinical evidence of nodal metastasis but cancer has high chance of occult nodal metastasis
Thyroid, Parathyroid glands pathologies
- Benign and malignant tumours
- Metabolism
- Calcium level
- Close proximity:
- Recurrent laryngeal nerve (CN10)
- nerve lies **underneath thyroid gland
- thyroid cancer may compress nerve —> **hoarseness
- surgical injury - Superior laryngeal nerve (CN10)
- external branch innervates **Cricothyroid muscles
- injury during dissection of **upper pole of thyroid - Trachea
Benign tumour of Thyroid and Parathyroids
Present as a mass
Present with endocrine disturbance
—> Hyperthyroidism in solitary adenoma (Too much Thyroid hormone) —> ipsilateral goitre
—> Hypercalcemia in parathyroid adenoma (Too much PTH) —> ureteric / renal stones
Investigation:
- Nuclear imaging: Special isotope scans to detect physiological abnormalities (functional scan) e.g. Tc99 for parathyroid, I131 for thyroid
RLN and SLN injury
Unilateral RLN injury
- ***hoarseness
- ***choking (∵ cannot close vocal cord: Adductors)
Bilateral RLN injury
- airway obstruction due to ***bilateral vocal cord palsy —> medical emergency (∵ cannot open vocal cord: Abductors)
External branch SLN injury
- unable to sing high pitch (∵ Cricothyroid —> lengthening of cord)
Incomplete bilateral palsy: affect Abductor only —> continue to Adduct —> cannot breathe
Complete bilateral palsy: affect Both —> cord at natural position (open) —> no problem
Larynx, pharynx and esophagus pathologies
- Muscle on cartilaginous skeleton
- Co-ordinated muscular function
3 mains functions
- Phonation
- Air and food passage
- Swallowing
Hypopharynx cancer
Small cancer
Local excision feasible
—> vocal cord spared
—> good voice
Larger cancer
Cord not moving —> invaded
—> surgical removal: need to remove whole larynx
—> alternative: Chemotherapy + Radiotherapy
***Physiological changes after laryngectomy
Stoma at trachea to replace nose
- Loss of speech
- Loss filter function of nose (breathe in cold and dry air)
- No smell (∵ bypass nose)
- Loss of humidification
- Ineffective cough
Skin, fascia, muscle etc. reconstruction
Head and neck area
—> skin graft, local flaps
Chest wall and other parts of body
—> ***fasciocutaneous flaps, myocutaneous flaps, bone, muscle, bowel
Reconstruction
—> trauma, tumour extirpation
Deltopectoral flap (NOT examined)
- Fasciocutaneous flap
- based on cutaneous perforator of internal mammary artery
- skin coverage for neck defect
