larynx lecture

8/10/2019 Larynx Lecture

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Learning Outcomes

Learning Outcomes:

Identify the aetiological factors associatedwith the development of tumours of thelarynx.

Describe the presenting symptoms oflaryngeal tumours

Identify the investigations that will enablethe correct diagnosis to be made.

Identify the TNM staging for such tumours.

Describe the oncological management ofpatients with tumours of the larynx.

Describe in detail the radiotherapytechniques that may be employed in themanagement of these patients, explainingthe rationale for each selected.

Describe the possible side effects fromradiotherapy treatment and explain howthey may be minimized.

Describe the daily management of patientsundergoing radiotherapy for laryngealtumours.


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Larynx anatomy review

Biological Function:

to act as a valve to prevent air from escaping the lungs,

to prevent foreign substances from entering the lungs,

trachea and glottis, e.g. while swallowing, the epiglottiscovers the opening to the larynx.

to forcefully expel foreign substances which threaten the

trachea, e.g. coughing

Non Biological Function:

The production of sound


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Skeleton of the larynxHyoid BoneThe yellowish bone in the image, it is

horseshoe shaped and is the onlybone in the body that floats,unconnected to another bone. It canbe felt by pressing a finger into thecrease where your chin becomes yourneck.

CartilagesThyroid - the "Adam's apple" onmen, this V shaped cartilage featuresa notch in the front which can be feltwith the edge of your thumb.Cricoid - a ring shaped cartilageconnected to the trachea, it is larger

in back where the arytenoid cartilagessit (not visible in this image).Trachea

Made up of a series of cartilaginousrings, the trachea can stretch, muchlike a vacuum cleaner hose. Compressit by swallowing, stretch it by tippingyour head back.
http://www.yorku.ca/earmstro/journey/images/larynx.gif


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Skeleton of the larynx

The Epiglottis

Functioning much like a "flap valve" on a

toilet, the epiglottis drops down in

swallowing to close off the entrance to the

larynx, thereby protecting the airway.

The Fat Pad

Sitting behind the Epiglottis is a pad of fat

(yellowish in the image above) which

cushions it as it rises.

The Arytenoid CartilagesThe arytenoids are pyramid shaped and sit

on top of the widest part of the cricoid

cartilage. The vocal folds are attached to

these cartilages and it is their movement

that opens and closes the glottis (the

space between the vocal folds).


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Anatomy of the Larynx

This image shows the larynxfrom the side, featuring the

vocal ligament, so that you

can visualize the placement of

the vocal folds within the

structure of the cartilages.


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Anatomy of the Larynx

This image shows the cartilages of

the larynx from above, giving an

excellent reference point for futureimages of the larynx as seen

through an endoscope, as they

really appear.


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Anatomy of the LarynxThe "true" vocal folds - are made up of fivelayers:

epithelium - the surface "skin" of the

larynx, which is continuous with the lining

of the mouth, pharynx and with the trachea

below the larynx.

lamina propria - three distinct layers, each

with a different consistency

superficial layer: a jelly-like

substance, close to the surface

intermediate layer: an elastic,

fibrous substance, like rubber

bands

deep layer: a thread-like

collagenous fibre layer

vocalis muscle: the main body of the vocal

fold, and very stiff


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Vocal cords: Inhalation

This image shows the vocal folds abducted for inhalation. You can see the two bumps of the of

the arytenoid cartilages near the bottom corners of the picture, the vocal folds are making a V

pointing at the thyroid cartilage, and you can see the shiny epiglottis at the top of the image,

like a crescent moon. Looking inside the glottis, you can make out the rings of the trachea.


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Vocal cords: Exhalation

In this image, the vocal folds are adducted for phonation on the exhaled breath.

You can see that the arytenoid cartilages have swung forwards and together to bring the

edges of the folds into contact. The folds are photographed in mid vibration; you can see the

degree to which the folds separate during each vibratory cycle (not much!). The folds appear

white in colour because there is very little blood flow to the fold tissue, and the arteries are

microscopic. However, if a blood vessel were to break, the results would be very dramatic, asthe tissue would quickly fill with blood, turning a deep red colour.


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Epidemiology

Cancer of the larynx is rare.

Around 2,300 people are diagnosed in the UK each year.

Fewer than 1 in every 100 cancers is a cancer of the

larynx. Cancer of the larynx is more common in men than in

women. There are around 5 times as many men

diagnosed as women.

More common in older people than in younger. There arevery few cases in people under 40 years of age.


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Aetiology

Smoking

Exposure to chemicals

Excessive drinking

Immunosuppression &

HPV virusPoor diet

Genetics


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Histology

85-95% of Laryngeal tumours are squamous cell

carcinoma

Others include: Verrucous carcinoma

Fibrosarcoma

Chondosarcoma

Minor salivary carcinomaAdenocarcinoma

Oat cell carcinoma

Giant and Spindle cell carcinoma


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Signs & Symptoms

Hoarseness

Difficulty in swallowing food

The feeling of a lump in the throat

Cough or shortness of breath

Halitosis

Unexplained Weight Loss

These symptoms are common in conditions other than cancer andmost people with these symptoms will not have laryngeal cancer.


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Clinical Investigations

Full body examination

Full medical history

Laryngoscopy / Transnasal oesophagostomy

Biopsy Blood tests

Chest x-ray

MRI (magnetic resonance imaging) scan

CT (computerised tomography) scan

Isotope bone scan

PET/CT


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Laryngoscopy

Carcinoma in-situ

T1 carcinoma of the larynx

T3 carcinoma of the larynx


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PET/CT


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TumourNM

TX :Indicates the primary tumour cannot be evaluated.

T0: No evidence of a tumour is found.

Tis: Describes a stage called carcinoma (cancer) in situ. This is a very earlycancer where cancer cells are found only in one layer of tissue.

When describing a later stage tumour, the larynx is divided into three regions: the

glottis, the supraglottis, and the subglottis.


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TumourNM- glottisT1: Describes a tumour that is limited to the vocal folds, but it does not affectmovement of the folds.

T1a: Describes a tumour in just the right or left vocal fold.

T1b: Describes a tumour in both vocal folds.

T2: Describes a tumour that has spread to the supraglottis and/or the subglottis. T2

also describes a tumour that affects the movement of the vocal fold, without paralyzing

the fold.

T3: Describes a tumour that is limited to the larynx and paralyzes at least one of the

vocal folds.

T4a: The tumour has spread to the thyroid cartilage and/or the tissue beyond the

larynx.

T4b: The tumour has spread to the area in front of the spine (prevertebral space), chest

area, or encases the arteries.


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TumourNM-supraglottisT1: Describes a tumour located in a single area above the vocal folds thatdoesnt affect movement of the vocal folds.

T2: Describes a tumour that started in the supraglottis, but has spread to the

mucus membranes that line other areas, such as the base of the tongue.

T3: Describes a tumour that is limited to the larynx with vocal fold involvementand/or has spread to surrounding tissue.

T4a: The tumour has spread through the thyroid cartilage and/or the tissue

beyond the larynx.

T4b: The tumour has spread to the area in front of the spine (prevertebral

space), chest area, or encases the arteries.


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T NodesM NX: Indicates that the regional lymph nodes cannot be evaluated.

N0: There is no evidence of cancer in the regional nodes.

N1: Indicates that cancer has spread to a single node on the same side as the primary tumorand the cancer found in the node is 3 cm or smaller.

N2: Describes any of the following conditions:

N2a: Cancer has spread to a single lymph node on the same side as the primary tumor, andis larger than 3 cm, but not larger than 6 cm.

N2b: Cancer has spread to more than one lymph node on the same side as the primarytumor, and none measure larger than 6 cm.

N2c: Cancer has spread to more than one lymph node on either side of the body, and nonemeasure larger than 6 cm.

N3: Indicates that the cancer found in the lymph nodes is larger than 6 cm.

Distant metastasis (for both larynx and hypolarynx). The M in the TNM system indicateswhether the cancer has spread to other parts of the body.


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TN Metastasis

MX: Indicates that distant metastasis cannot be

evaluated.

M0: Indicates that the cancer has not spread to other

parts of the body.

M1: Describes cancer that has spread to other parts of the

body


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Stage 0

Describes a carcinoma in situ (Tis), with no spread to

lymph nodes (N0) or distant metastasis (M0).


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Stage I

Describes a small tumour (T1), with no spread to lymph

nodes (N0) and no distant metastasis (M0).


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Stage II

Describes a tumour with some spread to nearby areas (T2), but has

not spread to lymph nodes (N0) or to distant parts of the body (M0).


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Stage III

Describes any larger tumour (T3), with no spread to regional lymph nodes (N0) or

metastasis (M0), or a smaller tumour (T1, T2) that has spread to regional lymphnodes (N1) but has no sign of distant metastasis (M0).


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Stage IVa

Describes any invasive tumour (T4a), with either no lymph node involvement (N0) orspread to only a single same-sided lymph node (N1), but no metastasis (M0). It is alsoused for any tumour (any T) with more significant spread to the lymph nodes (N2), but nometastasis (M0).


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Stage IVb

Describes any cancer (any T) with extensive spread to lymph nodes (N3), but no

metastasis (M0). For laryngeal cancer, it is also used for a very advanced localized

tumour (T4b). with or without lymph node involvement (any N), but no metastasis (M0).


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Stage IVc

Indicates there is evidence of distant spread (any T, any N,

M1).


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Grading

GX: Indicates the grade cannot be evaluated.

G1: Indicates the cells look more like normal tissue (welldifferentiated).

G2: The cells are only moderately differentiated.

G3: The cells dont resemble normal tissue (poorly

differentiated).


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Oncological Management

Standard treatments for patients with laryngeal cancer

include the following:

Radiation therapy alone.

Surgery

Concurrent chemoradiation.

Laser surgery.

Biological therapy.(National Cancer Institute, 2012)


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Surgery- early stage

The most common surgical procedures used to treat early laryngeal cancerinclude:

Partial laryngectomy. The removal of part of the larynx, preserving the voice.

The following are some of the different types of partial laryngectomies:

Supraglottic laryngectomy. The removal of the area above the vocal folds. Ifpart of the hypopharynx is to be removed with the cancer, this is called apartial pharyngectomy.

Cordectomy. The removal of a vocal fold.

Vertical hemilaryngectomy. The removal of one side of the larynx.

Supracricoid partial laryngectomy. The removal of the vocal folds and thearea surrounding them.


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Surgery- late stage Total laryngectomy. The removal of the entire larynx. During this operation, a

hole called a stoma is made in the front of the neck through the windpipe toallow the person to breathe. This is called a tracheostomy (see below).Because the vocal folds have been removed, people can no longer speakusing their vocal folds after a total laryngectomy. However, a speechpathologist can teach people to speak in a different way after the surgery.

Laryngopharyngectomy. A laryngopharyngectomy is the removal of the entirelarynx, including the vocal folds, and part or all of the pharynx. After thissurgery, doctors must reconstruct the pharynx using flaps of skin from theforearm, other parts of the body, or a segment of the intestine. Like a totallaryngectomy, people can no longer speak using the vocal folds and they mayalso have difficulty swallowing after laryngopharyngectomy. However, speechpathologists can help people learn to speak and swallow afterwards.

Tracheostomy. In both partial and total laryngectomies, the surgeon makes ahole called a stoma in the front of the neck into the windpipe or trachea. Atube is often inserted to keep the hole open. Air enters and leaves thewindpipe (trachea) and lungs through the stoma, allowing the person tobreathe.


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Laryngectomy

Partial Laryngectomy

In a partial laryngectomy,the stoma is usually

temporary. After recoveryfrom the partiallaryngectomy, the tube isremoved, the hole healsclosed, and the person can

then breathe and talk in thesame way as before thesurgery. In some cases, thevoice may be hoarse orweak.

Total Laryngectomy

In a total laryngectomy,

the stoma is permanent,

and the person breathes

through the stoma and

must learn to speak in a

new way.


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Surgery- neck dissection

If cancer has spread to the lymph nodes in the neck, a

neck dissection may be necessary.

There are several types of neck dissections, depending

on the stage and location of the cancer.

Some or all the lymph nodes in the neck may have to be

removed (partial neck dissection, modified neck

dissection, selective neck dissection). A

A patient may have varying degrees of stiffness in the

shoulder and the neck and loss of sensation in the neckafter this surgery.


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Laser surgery

http://www.youtube.com/watch?v=-_rNvLW1iX4

Watch the following clip to observe laser surgery for laryngeal carcinomapatients
http://www.youtube.com/watch?v=-_rNvLW1iX4http://www.youtube.com/watch?v=-_rNvLW1iX4http://www.youtube.com/watch?v=-_rNvLW1iX4http://www.youtube.com/watch?v=-_rNvLW1iX4


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Targeted therapy Targeted therapies refer to a group of medicines that are designed to target and disrupt one

or more of the biological processes that cancerous cells use to grow and reproduce.

A targeted therapy called cetuximab can be used to treat cases of stage three or stage fourlaryngeal cancer where it's not possible to use chemotherapy.

Cetuximab targets special proteins called epidermal growth factor receptors (EGFRs), which

are found on the surface of cancerous cells. EGFRs help the cancer to grow, so by targetingthem cetuximab can prevent the cancer from spreading.

Cetuximab is given intravenously which slowly delivers the first dose over the course of a fewhours. Further doses should take about an hour and are given weekly.

Most infusion reactions occur within 24 hours of treatment starting, so you'll be closelymonitored once your treatment begins. If you have symptoms of an infusion reaction, such as

a rapid heartbeat or breathing problems, anti-allergy medicines can be used to relieve themfor example, corticosteroids.

These measures mean that deaths resulting from infusion reactions in people takingcetuximab are very rare, occurring in less than 1 out of every 1,000 cases.

NHS Choices (2011)


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Targeted therapy

The side effects of cetuximab are usually mild and include:

skin rashes

feeling sick

diarrhoea breathlessness

eye inflammation (conjunctivitis)

Cetuximab can trigger allergic reactions in some people, such asa swollen tongue or throat.

Occasionally, the allergic reaction can be severe and life-threatening. This is known as an infusion reaction and it occursin about 1 in 35 people who take cetuximab.

NHS Choices (2011)


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Radiotherapy recommendations

Stage T1-2, N0 (Glottic & Supraglottic only):

Surgery/RT equivalent cure rate

RT alone offers 5 year local control rates of 75-90%in T1tumours

RT preferable

Stages T3-4, N+:

Surgery plus adjuvant RT in selected cases

Nodal disease:

RT to neck for N2-3 disease or N1 with extra -capsulardisease


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Recurrent Disease

Standard treatment options:

1.Selected patients with local recurrence may be retreated with moderate-doseexternal-beam radiation therapy using intensity-modulated radiation therapy,stereotactic radiation therapy, or intracavity or interstitial radiation to the site ofrecurrence.

2.In highly selected patients, surgical resection of locally recurrent lesions may beconsidered.

3.If a patient has metastatic disease or local recurrence that is no longer amenableto surgery or radiation therapy, chemotherapy should be considered.

Treatment options under clinical evaluation:

Clinical trials evaluating chemotherapy should be considered.

Stereotactic radiation for locally recurrent disease or persistence


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Radiotherapy Techniques

3D conformal treatment:2/3 beams, PTV + 1cm margin ant neck

Glottic Tumours:

55Gy/20 #/4 weeks 64Gy/32# /6.5 weeks

50Gy/16#/3 weeks

Other tumours:

66-70Gy/33-35#/7 weeks tomacroscopic disease

44-50Gy/22-25#/5 weeks tomicroscopic disease


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Radiotherapy Techniques

IMRT

Stereotactic

Arc therapy

NRAG Report (2007):

All Head neck patients must be treated using 4D

conformal radiotherapy by 2017.


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OAR

Brachial Plexus < 60Gy

Brainstem < 54Gy (60Gy point dose)

Eye < 35Gy

Inner/Middle Ears < 50Gy

Lacrimal Gland < 30Gy

Lens < 10Gy Mandible < 70Gy

Optic Chiasm < 50Gy

Optic NN < 54Gy

Parotid V24 < 50% (mean dose

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