4Parotid GlandBordersSuperior – 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 mandibleFacial 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.
6Submandibular 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 Wharton’s duct in anterior floor of the mouthLymphatic Drainage Lvl I – Lvl II- Lvl III
7Sublingual Gland 10% size of parotid gland Located anterior floor of the mouthBordersLateral –medial aspect of mandibleInferior –mylohyoid muscleLingual nerve courses adjacent to sublingual glandDrain into the floor of the mouth through Rivinus ductsLymphatic drainage – Lvl I- Lvl II- Lvl III
9Epidemiology Salivary tumors 7% of head and neck tumors Parotid tumors 10x more common then submandibular and 100x more common then lingualParotid 80% benign (pleomorphic adenoma)Submandibular 50% malignantSublingual majority (65-88%) are malignantEqual incidence between sexesRisk Factors: nutritional deficiency, exposure to ionizing radiation, UV exposure, genetic predisposition, EBV
10Pathology Benign Tumors Malignant tumors Pleomorphic Adenomas Parotid – mucopidermoid most common – low grade, slow growing cured by surgery aloneSubmandibular and minor salivary – adenoid cystic most common.
12Adenoid Cystic Cribiform pattern – differentiated Cribiform/solid pattern – moderately differentiatedSolid Features – undifferentiatedNatural history ranges from months to greater then 20 years.Lymph Node spread <5%
13Adenoid CysticPerineural spread common and can track along the cranial nerves back to the base of skull40% develop pulmonary mets but survival of years can occur with pulmonary mets so primary must be managed
15Metastatic Disease involving Parotid MechanismLymphatic spread – most common from skinHematogenous spread - lungDirect extension – skin or osseous sarcomas
16Staging T1 ≤ 2cm and no extraparenchymal extension T2 > 2cm but not >4cm without extraparenchymal extensionT3 >4cm and or extraparenchymal extensionT4a invades skin, mandible, ear canal and/or facial nerveT4b invades skull base and or pterygoid plates and or encases carotid artery
17Parotid Tumors Clinical presentation Evaluation Asymptomatic mass Cranial nerve palsey – inability to move one side of face, one shoulder, one side of tongue.EvaluationTrismus – to evaluate pterygoid involvementCT/MRIFNA in parotid tumors 90% sensitive and >95% specificNever perform incisional or excisional biopsy
18Parotid Tumors Lymph Nodes Distant Spread Rare in adenoid cystic 12% positive in clinically negative tumors.Size and grade are risk factors>4 cm 20% occult mets vs 4% in smaller tumorHigh grade 49% risk regardless of histologic type vs 7% for low or intermediateDistant SpreadLung25-35% risk for mucoepidermoid, adenoid cystic and malignant mixed tumors.Routine CXR
19Postoperative Radiation versus Surgery for Salivary Gland Tumors: Results from the literature Series# PTsFUP length (y)Prognastic factorsLC 5yS S/RSurv 5yS S/RMSKCC92S 10.5S/R 5.8Stage I/IIStage III/IVPositive nodesHigh-GradeJH87All patientsMDACC1557.5PMH27110-(RFS)
20Submandibular tumor Clinical presentation Evaluation Asymptomatic mass Painful mass as enlargesCranial nerve palsey –decrease sensation in ipsilateral lower teeth, lip and gums, inability to move ipsilateral oral tongue or inbality to move part of face.EvaluationCT/MRI – help to distinguish a pseudomassFNA in submandibular tumors useful only if reveals a malignancy.All lesions approached with a submandibular triangle dissectionAlmost never perform incisional or excisional biopsy.
21Submandibular Tumors Lymph Nodes Distant Spread 28% risk in submandibular tumorsLvl I, II and III most common sitesDistant SpreadLung >bone and liver
22Sublingual Tumors Clinical presentation Evaluation Asymptomatic swelling in floor of mouthCranial nerve palsey – ipsilateral loss of sensation of one side of tongue.EvaluationCT/MRIMost tumors are malignant so FNA only useful if maligantAlways resect with a formal cancer surgery
23Sublingual Tumors Lymph Nodes Distant Spread Higher risk of LN spread then parotid tumorsLvl I is first site of drainageDistant SpreadLung > bones and liver
24Treatment Surgery -Parotid 90% confined to superficial lobe – perform superficial parotidectomyIf adjacent to deep lobe - total parotidectomyIf invades adjacent soft tissue – radical parotidectomyNever perform piecemeal excision in an attempt to preserve facial nerveNerve grafting can be performed and RT can start3-4 wk post op without adverse affectsFrey’s syndrome – (gustatory sweating) due to redirection of parasympathetic and sympathetic nerve fibers to the dermal sweat glands
25Treatment Surgery - Submandibular Surgery – Sublingual Small tumor – gland excisionECE –En bloc resection with extended supraomohyoid neck dissectionSurgery – SublingualSmall and localized can resect without submandibular glandGenerally requires resection of submandibular gland as well.
26Treatment Radiation – Surgically unresectable tumors EBRT with photon and or electrons with conventional or altered fractionationBrachytherapy ± EBRTNeutron therapy
27Treatment Radiation – Surgically unresectable tumors EBRT Equivalent control rates as for equivalent head and neck squamous cell cancersEarly stage % control ratesLate and Recurrent 50-70%HyperfractionationWang and Goodman reported on 14 patients using 1.6 Gy bid to Gy.5 yr LCR 82%
28Treatment Radiation – Surgically unresectable tumors Brachytherapy Used frequently with recurrent or advanced disease5 yr LCR 60%Neutron therapyBiologic effect of neutrons less effected by hypoxiaLethal effects less dependent on cell cycleRepair of sublethal damage in malignant cells is lessRBE > 2.6Severe late effect greater 17% versus 7%Improved local control but no diff in overall survival
29Treatment Postoperative Radiation Indications Close surgical margins (deep lobe parotid tumors, facial nerve sparing)Microscopically positive marginHigh grade including adenoid cysticInvolvement of skin, bone, nerve (gross or extensive perineural invasion), tumor extension beyond capsule with periglandular and soft tissue invasionLN spreadLarge tumors requiring radical resectionTumor spillageRecurrence
30Treatment Postoperative Radiation Technique LCR with surgery and post op RTT1 100% T2 83% T3 80% T4 43%TechniqueParotidElectrons – lateral en faceMixed beam – 50-80% electron weighting lateral en face or wedge pair.Photons - wedge pair or IMRT
31Treatment Technique Portal margins – Parotid Superior – top of zygomatic boneInferior – hyoid bone – thyroid notchAnterior - 2cm ant to upper second molarPosterior – posterior to mastoid tip.Lateral - 2 cm flash on cheekMedial – 2 cm medial from ipsilateral oropharyngeal area.Electron portal margins are 1 cm greaterUsually 12 MeV- 16 MeV energy used
33Treatment Technique Portal margins – Submandibular Superior – 1cm above upper border of tongueInferior – Hyoid bone-thyroid notch interspaceAnterior – anterior aspect of mental symphysisPosterior – BOT- jugulodigastric nodal areaLateral – 2 cm flash of ipsilateral mandibleMedial – midline of tongue
34Treatment Technique Portal margins – Sublingual Superior – 1cm above upper border of tongueInferior – Hyoid bone-thyroid notch interspaceAnterior – anterior aspect of mental symphysisPosterior – posterior aspect of the ascending mandibular ramusLateral – 2 cm flash of ipsilateral mandibleMedial – 2cm past midline
35Treatment Dosage – Primary treatment Accelerated fractionation with a delayed concomitant boostPhase I 1.8Gy daily to 36 GyPhase II 1.8 Gy as in phase I in AM x 10 fractions to 54Gy and > 6hrs 1.6 Gy to GTVx 10 fractions to 16 GySpinal cord dose < 45 Gy.IMRT to 70 Gy for GTV 63 Gy CTV 1 and 56 Gy CTV2
36Treatment Dosage – Post op treatment Administered within 6 weeks of surgeryHigh 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.
37Side effects Salivary fxn Trismus 80% of saliva produced by major salivary glandsLoss of salivary fxn complete >35 GyDose limit to spare salivary function is 26 Gy.TrismusTMJ and masseter muscle < 50Gy. PT during and after treatment
38Adenoid Cystic Carcinoma Post op RT always recommendedPost op RT of entire pathway of adjacent cranial nerve to base of skull always recommendedRegional LN spread is 15% and elective nodal irradiation is not standardSurgery alone LCR 25-40% +RT 75%-80%
39Pleomorphic AdenomaBenign tumor – 75% of all parotid epithelial tumors.Surgery is treament of choiceMultiply recurrent tumors can be treated with RT>3 local recurrencesLarge lesion with surgically inadequite marginMicroscopically positive surgical marginsMacroscopic residual diseaseMalignant transformation50-60 Gy dose
40Minor Salivary TumorsHighest concentrations of the glands in the oral cavity, palate, nasal cavity and paranasal sinusGlandsNo glands located in the gingiva or anterior half of the hard palate50% malignantAdenoid cystic is most common malignant histology seen.
41Quiz What is the most common tumor of minor salivary glands A. Pleiomorphic AdenomaB. Adenoid cystic carcinomaC. Mucoepidermoid carcinomaD. Squamous cell carcinoma
42Quiz What are the borders of the parotid gland? SuperiorInferiorAnteriorPosteriorZyogomatic archHyoid boneAscending ramus of mandibleMastoid process
43Quiz The most common parotid tumor is A. Pleomorphic adenoma B. Mucoepidermoid carcinomaC. Adenoid cystic carcinomaD. Detroit tigers
44Quiz Most parotid tumors are ___________ A. Benign 60% B. Benign 80% C. Malignant 60%D. Malignant 80%
45QuizAll of the following are true regarding adenoid cystic carcinoma except?A. It rarely spreads to Lymph nodesB. It is a common minor salivary tumorC. It typically does not involve nervesD. 40% develop pulmonary metastasis
46QuizAdenoid cystic of parotid s/p parotidectomy with perineural invasion, what is treatment field?A. Post op bedB. Post op bed and BOSC. Post op bed and BOS and ipsilateral neckD. Post op bed and BOS and bilat neck
47QuizWhat is treatment of choice for cystic pleomorphic adenoma? After rupture or residual?Superficial parotidectomy. If intraop cystic rupture, add post op RT
48Quiz How are parotid tumors staged? ≤ 2cm2-4 cmExtraparenchymal, No VII involvement ± 4-6cm>6cm, BOS, CN VII
49QuizAll of the following are indication for RT in pleiomorphic adenoma except?A. Deep lobe involvementB. Large >5cmC. Recurrent tumorD. Positive margin
50Quiz What seperates the superficial parotid from the deep lobe? Facial Nerve
51QuizIntraparotid lymph node and a single 3cm neck node what is the most likely primary?SkinParotid
52Quiz True/False series. Indication for post-op RT for parotid tumors Close but clear margin on benign pleomorphic adenoma < 3cmAdenoid cystic with clear marginHigh grade mucopidermoidCN VII sacrifice for tumor close to nerve but not invading nerve