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semester 3  
  :: Notes :: 
   
 
Lecture 10 and 11

LARYNX:

Anatomy:  made up of 3 regions

  • Glottis (true vocal cords / vocal folds)
  • Supraglottis (false cords / they close when we swallow, provide protection from pleural aspiration)
  • Subglottis

 

Etiology: 

  • #1 risk factor is smoking (risk falls significantly after 5 years after quitting and is almost gone by 10 years)
  • GERD (gastro-esophogeal reflux disease – backflow of food mixed with gastric juices)

 

Epidiemiology:

  • 2 % of all cancers
  • 2nd to Lip in head and neck cancers
    • Glottic accounts for  65%
    • Supraglottic accounts for 25-33%
  • Larynx cancer is a male-dominated disease (90%)
  • Peak incidence in the 50-60 year age-group

 

 

Symptoms:

  • Most common symptoms:
    • Glottic – hoarsness followed by sore throat and otalgia
    • Supraglottic – sore throat or lump in throat, mass in neck, weight loss, aspiration (food in lungs)

 

Workup:

  • Endoscopy
    • Asses mobility of cords (normal, impaired, fixated)
  • Biopsy while Endoscopy is being done

 

 

Specific Sites of Laryngeal Cancer:

  • Glottic :
    • lesions are well to moderately differentiated, with supraglottic lsesions being less differentiated and more aggressive
    • tumors develop on vocal cord (65-75% of glottic lesions appear on the anterior 2/3 of one cord and the most common site is the Anterior Commisure)
    • spread superficially onto the membrane that covers the cord
    • RT is the primary choice of Tx for nonfixed surface lesions that have not extensively infiltrated muscle, bone, or cartilage
    • Glottic cancer is treated with opposing lat fields, 4x4cm to 5x5cm(Co60). Daily doses can be 200-220 cGy, up to a total dose of 6000-7000 cGy.
    • Large T3/T4, transglottic lesions are treated with RT alone

     

  • Supraglottic:
    • Surgery can control 80% of supraglottic T1/T2 lesions, whereas RT offers 75% local control
    • Tends to have already spread by time of diagnosis (larger lesions at time of diagnosise)
      • Usually there are no early symptoms
      • Spread to Lymphatics (Delphian Nodes) 50 % of the time
    • RT alone for T3/T4 to supraglottic lesions is contraindicated
    • Relapses are treated with surgery
    • Tumor dose needed to achieve control is 6600-7000 cGy + e-boost of cervical lymph nodes

 

  • Subglottic
    • Treated with total laryngectomy , with post-op RT given for any residual disease

 

Staging:

T Stages of Glottic Cancer :

T1: The tumor is limited to the true vocal cord(s), and the vocal cords move normally; includes anterior and posterior commisure (can be on both sides of vocal cord)

T2: The tumor extends to the supraglottis and/or subglottis, and/or there is normal or impaired vocal cord  movement.

T3: The tumor is limited to the larynx with vocal cord fixation

T4: Cartilage destruction and/or extension out of larynx

 

T Stages of Supraglottic Cancer:

The T stage of cancer of the supraglottis is based on how many subsites (different parts of the  larynx) are involved and how far outside the larynx the cancer has spread.

T1: confinment to site of origin; and the vocal cords move normally. (can be on both sides of cord)

T2: extension to glottis or adjacent supraglottic site; normal or impaiured mobility

T3: The tumor is limited to the larynx, and there is vocal cord fixation (lack of movement)  and/or extension into hypopharynx or preepiglottic space

T4: Massive Tumor; cartilage destruction and/or extension out of larynx

 

T Stages for Subglottic

T1: confinment to subglottic region

T2:  glottic extension; normal or impaired mobility

T3:  confinment to larynx proper; cord fixation

T4:  Massive tumor; cartilage destruction and/or extension out of larynx

 

N (Regional Lymph Node) Stages of Laryngeal Cancers:

The N staging is the same for laryngeal and hypopharyngeal cancers. The stages are as follows: NX: The lymph nodes cannot be assessed (information not available). N0: There is no evidence of spread to the lymph nodes.

NX:  nodes cannot be assesed

N0: no clinically positive nodes

N1: The cancer has spread to a single lymph node not larger than 3 cm in diameter.  The lymph node is on the same side of the neck (right or left) as the primary tumor.

N2: There is spread to 1 or more lymph node(s) between 3 cm and 6 cm (about 21⁄2 inches) in  diameter.

N2a: There is spread in 1 lymph node between 3 cm and 6 cm, on the same side of the neck as the  origin of the cancer.

N2b: There is spread in multiple lymph nodes, none larger than 6 cm, and all on the same side of  the neck as the origin of the cancer.

N3: There is spread to 1 or more lymph nodes larger than 6 cm.

 

M (Distant Metastasis) Stages of Laryngeal Cancers:

The M staging for all head and neck cancers, including laryngeal and hypopharyngeal cancers, is  the same. The stages are as follows:

MX: Information not available. Unable to tell if distant metastasis is present.

M0: No distant metastasis.

M1: Distant metastasis present.

 

Treatment Options by Stage:

CIS (carcinoma in situ)  :  Radiation Therapy or Cordectomy (pull off epithelial lining of the cord)

T1 – T2 : Radiation Therapy

T3 : debatable between Surgery or Radiation Therapy

Favorable T3 tumors - Radiation Therapy

Unfavorable T3 tumors – Surgery

T4 : Surgery with postoperative Radiation

 

Techniques used for Radiation Therapy:

Glottic: small fields 4X4 or 5X5(Co60)

  • Use straight laterals
  • Obliques will be used if the adams apple is well defined

 

T1 – T2 – 90% survival rate with treatment

T3 – T4 – larger fields 8X8 (BID is superior treatment)  you give the same treatment you would give to a cancer of the supraglottic

Recurrance usually occurs within 2 years

There is a 15 – 25% chance of developing a second primary