Salivary Gland Tumors

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Salivary Gland Tumors

• Marka Crittenden M.D. Ph.D.

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Anatomy

• Major Glands
• Parotid, submandibular and sublingual glands
• Minor Glands
• Hundreds residing in the oral cavity, pharynx and
  paranasal sinuses.

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Major Salivary Glands
?
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Parotid Gland

• Borders
• Superior zygomatic arch.
• Posterior angle of mandible under earlobe
  toward the mastoid tip.
• Inferior extends to the inferior aspect of the
  angle of mandible toward hyoid bone.
• Medial borders of the parapharyngeal-base of
  skull.
• Lateral below the skin of the preauricular
  cheek-upper neck.
• Anterior wraps around ascending ramus of
  mandible
• Facial nerve divides the gland into the
  superficial (80 ) and deep lobe (20)
• Parotid duct (Stensons) is 5 cm long and opens
  opposite the second molar.
• Lymphatic drainage periparotid/intraparotid
  lvl I lvl II- lvl III.
• Accessory parotid lobe Present in 20 of
  patients.

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Submandibular Gland

• Borders
• Lateral proximal half of the mandible.
• Posterior anterior to but near the low anterior
  margin of the parotid gland.
• Inferior approaches the level of the hyoid
  bone.
• Majority of gland lies over the external surface
  of the mylohyoid muscle.
• Lateral to and abuts the lingual and hypoglossal
  nerve and is medial to the marginal mandibular
  and cervical branch of the facial nerve.
• Drains through Whartons duct in anterior floor
  of the mouth
• Lymphatic Drainage Lvl I Lvl II- Lvl III

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Sublingual Gland

• 10 size of parotid gland
• Located anterior floor of the mouth
• Borders
• Lateral medial aspect of mandible
• Inferior mylohyoid muscle
• Lingual nerve courses adjacent to sublingual
  gland
• Drain into the floor of the mouth through Rivinus
  ducts
• Lymphatic drainage Lvl I- Lvl II- Lvl III

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Epidemiology

• Salivary tumors 7 of head and neck tumors
• Parotid tumors 10x more common then submandibular
  and 100x more common then lingual
• Parotid 80 benign (pleomorphic adenoma)
• Submandibular 50 malignant
• Sublingual majority (65-88) are malignant
• Equal incidence between sexes
• Risk Factors nutritional deficiency, exposure to
  ionizing radiation, UV exposure, genetic
  predisposition, EBV

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Pathology

• Benign Tumors
• Pleomorphic Adenomas
• Malignant tumors
• Parotid mucopidermoid most common low grade,
  slow growing cured by surgery alone
• Submandibular and minor salivary adenoid cystic
  most common.

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Adenoid Cystic

• Cribiform pattern differentiated
• Cribiform/solid pattern moderately
  differentiated
• Solid Features undifferentiated
• Natural history ranges from months to greater
  then 20 years.
• Lymph Node spread lt5

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Adenoid Cystic

• Perineural spread common and can track along the
  cranial nerves back to the base of skull
• 40 develop pulmonary mets but survival of 10-20
  years can occur with pulmonary mets so primary
  must be managed

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Metastatic Disease involving Parotid

• Mechanism
• Lymphatic spread most common from skin
• Hematogenous spread - lung
• Direct extension skin or osseous sarcomas

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Staging

• T1 2cm and no extraparenchymal extension
• T2 gt 2cm but not gt4cm without extraparenchymal
  extension
• T3 gt4cm and or extraparenchymal extension
• T4a invades skin, mandible, ear canal and/or
  facial nerve
• T4b invades skull base and or pterygoid plates
  and or encases carotid artery

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Parotid Tumors

• Clinical presentation
• Asymptomatic mass
• Cranial nerve palsey inability to move one side
  of face, one shoulder, one side of tongue.
• Evaluation
• Trismus to evaluate pterygoid involvement
• CT/MRI
• FNA in parotid tumors 90 sensitive and gt95
  specific
• Never perform incisional or excisional biopsy

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Parotid Tumors

• Lymph Nodes
• Rare in adenoid cystic
• 12 positive in clinically negative tumors.
• Size and grade are risk factors
• gt4 cm 20 occult mets vs 4 in smaller tumor
• High grade 49 risk regardless of histologic type
  vs 7 for low or intermediate
• Distant Spread
• Lung
• 25-35 risk for mucoepidermoid, adenoid cystic
  and malignant mixed tumors.
• Routine CXR

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Postoperative Radiation versus Surgery for
Salivary Gland Tumors Results from the literature
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Submandibular tumor

• Clinical presentation
• Asymptomatic mass
• Painful mass as enlarges
• Cranial nerve palsey decrease sensation in
  ipsilateral lower teeth, lip and gums, inability
  to move ipsilateral oral tongue or inbality to
  move part of face.
• Evaluation
• CT/MRI help to distinguish a pseudomass
• FNA in submandibular tumors useful only if
  reveals a malignancy.
• All lesions approached with a submandibular
  triangle dissection
• Almost never perform incisional or excisional
  biopsy.

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Submandibular Tumors

• Lymph Nodes
• 28 risk in submandibular tumors
• Lvl I, II and III most common sites
• Distant Spread
• Lung gtbone and liver

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Sublingual Tumors

• Clinical presentation
• Asymptomatic swelling in floor of mouth
• Cranial nerve palsey ipsilateral loss of
  sensation of one side of tongue.
• Evaluation
• CT/MRI
• Most tumors are malignant so FNA only useful if
  maligant
• Always resect with a formal cancer surgery

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Sublingual Tumors

• Lymph Nodes
• Higher risk of LN spread then parotid tumors
• Lvl I is first site of drainage
• Distant Spread
• Lung gt bones and liver

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Treatment

• Surgery -Parotid
• 90 confined to superficial lobe perform
  superficial parotidectomy
• If adjacent to deep lobe - total parotidectomy
• If invades adjacent soft tissue radical
  parotidectomy
• Never perform piecemeal excision in an attempt to
  preserve facial nerve
• Nerve grafting can be performed and RT can
  start3-4 wk post op without adverse affects
• Freys syndrome (gustatory sweating) due to
  redirection of parasympathetic and sympathetic
  nerve fibers to the dermal sweat glands

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Treatment

• Surgery - Submandibular
• Small tumor gland excision
• ECE En bloc resection with extended
  supraomohyoid neck dissection
• Surgery Sublingual
• Small and localized can resect without
  submandibular gland
• Generally requires resection of submandibular
  gland as well.

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Treatment

• Radiation Surgically unresectable tumors
• EBRT with photon and or electrons with
  conventional or altered fractionation
• Brachytherapy EBRT
• Neutron therapy

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Treatment

• Radiation Surgically unresectable tumors
• EBRT
• Equivalent control rates as for equivalent head
  and neck squamous cell cancers
• Early stage 71-100 control rates
• Late and Recurrent 50-70
• Hyperfractionation
• Wang and Goodman reported on 14 patients using
  1.6 Gy bid to 65-70 Gy.
• 5 yr LCR 82

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Treatment

• Radiation Surgically unresectable tumors
• Brachytherapy
• Used frequently with recurrent or advanced
  disease
• 5 yr LCR 60
• Neutron therapy
• Biologic effect of neutrons less effected by
  hypoxia
• Lethal effects less dependent on cell cycle
• Repair of sublethal damage in malignant cells is
  less
• RBE gt 2.6
• Severe late effect greater 17 versus 7
• Improved local control but no diff in overall
  survival

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Treatment

• Postoperative Radiation
• Indications
• Close surgical margins (deep lobe parotid tumors,
  facial nerve sparing)
• Microscopically positive margin
• High grade including adenoid cystic
• Involvement of skin, bone, nerve (gross or
  extensive perineural invasion), tumor extension
  beyond capsule with periglandular and soft tissue
  invasion
• LN spread
• Large tumors requiring radical resection
• Tumor spillage
• Recurrence

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Treatment

• Postoperative Radiation
• LCR with surgery and post op RT
• T1 100 T2 83 T3 80 T4 43
• Technique
• Parotid
• Electrons lateral en face
• Mixed beam 50-80 electron weighting lateral en
  face or wedge pair.
• Photons - wedge pair or IMRT

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Treatment

• Technique
• Portal margins Parotid
• Superior top of zygomatic bone
• Inferior hyoid bone thyroid notch
• Anterior - 2cm ant to upper second molar
• Posterior posterior to mastoid tip.
• Lateral - 2 cm flash on cheek
• Medial 2 cm medial from ipsilateral
  oropharyngeal area.
• Electron portal margins are 1 cm greater
• Usually 12 MeV- 16 MeV energy used

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Treatment

• Technique
• Portal margins Submandibular
• Superior 1cm above upper border of tongue
• Inferior Hyoid bone-thyroid notch interspace
• Anterior anterior aspect of mental symphysis
• Posterior BOT- jugulodigastric nodal area
• Lateral 2 cm flash of ipsilateral mandible
• Medial midline of tongue

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Treatment

• Technique
• Portal margins Sublingual
• Superior 1cm above upper border of tongue
• Inferior Hyoid bone-thyroid notch interspace
• Anterior anterior aspect of mental symphysis
• Posterior posterior aspect of the ascending
  mandibular ramus
• Lateral 2 cm flash of ipsilateral mandible
• Medial 2cm past midline

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Treatment

• Dosage Primary treatment
• Accelerated fractionation with a delayed
  concomitant boost
• Phase I 1.8Gy daily to 36 Gy
• Phase II 1.8 Gy as in phase I in AM x 10
  fractions to 54Gy and gt 6hrs 1.6 Gy to GTVx 10
  fractions to 16 Gy
• Spinal cord dose lt 45 Gy.
• IMRT to 70 Gy for GTV 63 Gy CTV 1 and 56 Gy CTV2

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Treatment

• Dosage Post op treatment
• Administered within 6 weeks of surgery
• High Risk 2.0 Gy/fx to 60Gy and 1.8Gy/fx to 63Gy.
  
• Small volume known microscopic disease 66 Gy.
• Elective at risk 50 Gy (2.0Gy/fx) 54 Gy(1.8Gy/fx)
• Gross residual 70Gy.

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Side effects

• Salivary fxn
• 80 of saliva produced by major salivary glands
• Loss of salivary fxn complete gt35 Gy
• Dose limit to spare salivary function is 26 Gy.
• Trismus
• TMJ and masseter muscle lt 50Gy. PT during and
  after treatment

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Adenoid Cystic Carcinoma

• Post op RT always recommended
• Post op RT of entire pathway of adjacent cranial
  nerve to base of skull always recommended
• Regional LN spread is 15 and elective nodal
  irradiation is not standard
• Surgery alone LCR 25-40 RT 75-80

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Pleomorphic Adenoma

• Benign tumor 75 of all parotid epithelial
  tumors.
• Surgery is treament of choice
• Multiply recurrent tumors can be treated with RT
• gt3 local recurrences
• Large lesion with surgically inadequite margin
• Microscopically positive surgical margins
• Macroscopic residual disease
• Malignant transformation
• 50-60 Gy dose

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Minor Salivary Tumors

• Highest concentrations of the glands in the oral
  cavity, palate, nasal cavity and paranasal sinus
• 500-700 Glands
• No glands located in the gingiva or anterior half
  of the hard palate
• 50 malignant
• Adenoid cystic is most common malignant histology
  seen.

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Quiz

• What is the most common tumor of minor salivary
  glands
• A. Pleiomorphic Adenoma
• B. Adenoid cystic carcinoma
• C. Mucoepidermoid carcinoma
• D. Squamous cell carcinoma

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QuizWhat are the borders of the parotid gland?

• Superior
• Inferior
• Anterior
• Posterior

• Zyogomatic arch
• Hyoid bone
• Ascending ramus of mandible
• Mastoid process

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Quiz

• The most common parotid tumor is
• A. Pleomorphic adenoma
• B. Mucoepidermoid carcinoma
• C. Adenoid cystic carcinoma
• D. Detroit tigers

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Quiz

• Most parotid tumors are ___________
• A. Benign 60
• B. Benign 80
• C. Malignant 60
• D. Malignant 80

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Quiz

• All of the following are true regarding adenoid
  cystic carcinoma except?
• A. It rarely spreads to Lymph nodes
• B. It is a common minor salivary tumor
• C. It typically does not involve nerves
• D. 40 develop pulmonary metastasis

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Quiz

• Adenoid cystic of parotid s/p parotidectomy with
  perineural invasion, what is treatment field?
• A. Post op bed
• B. Post op bed and BOS
• C. Post op bed and BOS and ipsilateral neck
• D. Post op bed and BOS and bilat neck

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Quiz

• What is treatment of choice for cystic
  pleomorphic adenoma? After rupture or residual?
• Superficial parotidectomy. If intraop cystic
  rupture, add post op RT

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QuizHow are parotid tumors staged?

• T1
• T2
• T3
• T4

• 2cm
• 2-4 cm
• Extraparenchymal, No VII involvement 4-6cm
• gt6cm, BOS, CN VII

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Quiz

• All of the following are indication for RT in
  pleiomorphic adenoma except?
• A. Deep lobe involvement
• B. Large gt5cm
• C. Recurrent tumor
• D. Positive margin

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Quiz

• What seperates the superficial parotid from the
  deep lobe?
• Facial Nerve

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Quiz

• Intraparotid lymph node and a single 3cm neck
  node what is the most likely primary?
• Skin
• Parotid

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QuizTrue/False series. Indication for post-op RT
for parotid tumors

• False
• True
• True
• False

• Close but clear margin on benign pleomorphic
  adenoma lt 3cm
• Adenoid cystic with clear margin
• High grade mucopidermoid
• CN VII sacrifice for tumor close to nerve but not
  invading nerve

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