Refresher Course EAR TUMOR. Sasikarn Chamchod, MD Chulabhorn Hospital

Transcription

1 Refresher Course EAR TUMOR Sasikarn Chamchod, MD Chulabhorn Hospital Reference: Perez and Brady s Principles and Practice of radiation oncology sixth edition

2 Outlines Anatomy Epidemiology Clinical presentations Diagnostic workups Prognostic factors Staging General Management Radiation Treatment Techniques Sequelae of treatment

3 Anatomy 1, EAC; 2, mastoid air cells; 3, tegmen mastoideum; 4, tegmen tympani; 5, tympanic segment of the facial nerve; 6, labyrinthine segment of the facial nerve; 7, petrous apex; 8, basal turn of the cochlea; 9, interscalar septum; 10, middle turn of the cochlea; 11, carotid canal; 12, tendon of the tensor tympani; 13, lateral process of the malleus; 14, lateral malleal ligament; 15, malleus (head).

4 Epidemiology Tumors of the external ear most commonly in years men > women CA of pinna is most often cutaneous related to sun Predisposing factors: otorrhea chronic ulcerations from trauma chronic eczema chronic dermatologic conditions

5 Epidemiology CA of the middle ear & external auditory canal rare (1 per million people) more common in years women > men

6 Clinical Presentations Pruritus and pain are common Swelling behind the ear Decreased hearing Facial paralysis in advanced cases In the bony canal have more effective barrier, and progress predominantly along the canal, invading the middle ear or the cartilaginous part of the canal Distant metastases are rare

7 Basal cell carcinoma Squamous cell carcinoma

8 Diagnostic Workups History exam for CN assessment of LN Laboratory CBC, Blood chemistry Radiographic CT MRI (selected (optional) Biopsy Other Audiology testing

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10 Preoperative CT scan (a) and MRI (b) of the patient with tumor involving the middle ear and mastoid, with erosion of the tegmen and extension into the petrous apex and the ITF.

11 Pathologic Classification M/C SCC LN metastases 10 common sites of LN are the parotid gland, the upper deep cervical, and the postauricular nodes basal cell adenoid cystic embryonic rhabdomyosarcomas

12 Prognostic Factors External more easily controlled than middle ear or early mostly adequate surgery or RT Presence of large lesions involving the middle ear and extend into the temporal bone is a poor prognostic and more difficult to treat

13 Prognostic Factors No correlate between tumor differentiation, positive margins, or PNI and survival, although they may serve as a predictor for local control in tumors involving the temporal bone CN VII palsy associated with middle ear tumors indicates poor local control Spread to the LN usually indicates a poor prognosis

14 The 7th edition of AJCC staging manual includes the external ear in under Cutaneous SCC and Other Cutaneous Carcinomas

15 No staging of ear tumor

16 TNM Staging Classification for Cutaneous SCC Staging: Non melanoma

17 General Management: External Ear Most often treated with limited surgery or ERT Early stages with megavoltage electron beam local control 80% et al. mean F/U 2.4 years for 115 of the pinna CA 5 year cure rate of 78% total dose Gy in Gy/F 2 3 times per wk

18 General Management: External Ear benefit if the lesion invade cartilage or extends into the auditory SCC with Sx alone recurrence rate 14% Mohs surgery is another option, LR rates 5% advanced lesions involving the ear canal are managed with RT and surgery

19 General Management: External Ear Treatment of LN is normally not required for early stages of external ear tumors Afzelius et indicate that lesions > 4 cm and those with cartilage invasion have an increased risk of LN spread recommend prophylactic neck dissection Most reports do not agree with this approach because the chance of LN involvement is only 16%

20 General Management: External Ear Radical Sx followed by PostopERT is an acceptable advanced lesions of the external auditory lesions in the middle ear and mastoid Pfreundner et al. recommended a postoprt Gy for negative 66 Gy for positive margins

21 General Management: External Ear Lesions of the outer part of the auditory require local at least a 1 cm margin if no invasion of surgery performed through a U shaped incision with elevation of the flap from a split thickness skin graft is required to cover the deficit along the auditory canal If the tumor involves the bony auditory canal but does not involve the middle ear or the mastoid, a partial temporal bone resection may be necessary

22 General Management: External Ear

23 General Management: Middle Ear and Temporal Bone Surgical options include subtotal temporal bone resection, total temporal resection, lateral temporal resection, or mastoidectomy Complete resection with clear margins may be difficult because important structures around the temporal bone PostopERT is recommended and increases local control CMT has not been beneficial Preoperative CCRT suggested improvement in survival of advanced disease, but additional trials are necessary.

24 Radiation Therapy Techniques Tumors involving the with megavoltage electrons or with superficial or orthovoltage fields can be round or polygonal, around the tumor to spare surrounding normal small, superficial tumors need margins 1 more extensive lesions require large portals, encompass the entire pinna or external canal and require 2 3 cm margins

25 Treatment portal for tumor of the middle ear involving the petrous bone. The mastoid is included in irradiated volume.

26 Radiation Therapy Techniques Lesions involve treated Gy/F to prevent cartilage doses 66 Gy over 6.5 weeks are required

27 Radiation Therapy Techniques Large lesions of the external auditory treated with RT or combined with portals should encompass the entire ear and temporal bone with margin 3 volume treated include the ipsilateral preauricular, postauricular, and subdigastric jugulodigastric LN is not necessary IMRT can help improve target coverage and spare normal critical structures

28 Treatment plan for EAC SCC GTV is in red High-risk CTV is in green Standard-risk CTV is in yellow Dose color wash

29 Radiation Therapy High risk CTV = GTV + margin cm Dose Gy/33 35 F (2 Standard risk CTV = High risk CTV + margin cm include preauricular nodes + postauricular nodes + parotid gland + ipsilateral cervical LN level II Dose 63 Gy/35 F (1.8 Low risk CTV considered in advanced and aggressive tumors Low risk CTV = ipsilateral cervical LN level III and IV + contralateral cervical LN level II Dose 56 Gy/ 35 F (1.6 PTV = CTVs + margin 3 5 mm

30 Radiation Therapy Techniques Postop IMRT of the external auditory canal and middle High risk CTV = original tumor + surgical bed + soft tissue invasion + areas + residual disease or positive margins dose Gy/30 33 F Gy (2 Standard risk CTV = CTV1 + margin cm + ipsilateral cervical LN level II + parotid region dose Gy/27 30 F (1.8 Low risk CTV = ipsilateral cervical LN level III and IV ± contralateral cervical LN level II dose of Gy/25 27 F (1.6 optimized cover 95% of PTV with 100% of the prescribed

31 Radiation Therapy Techniques Extremely advanced tumors high energy ipsilateral electron beam therapy (16 20 MeV) alone or mixed with photons (4 6 wedge pair (superior inferiorly angled beams) techniques using low energy photons or IMRT IMRT is a reasonable option if nodal coverage Doses Gy over 6 7 weeks

32 Radiation Therapy Techniques Most pts. receiving RT to the middle ear and temporal bone regions benefit from immobilization devices such as the Aquaplast system. When electron beam RT is used, use of water bolus in the external auditory canal and concha may reduce the auricular complications.

33 Results of Therapy

34 Palliative Radiation Therapy Palliation RT in recurrent or advanced disease Pain relief is in 61% of pts with tumors of the auditory canal and middle ear. Recurrences after RT may be re treated with lowdose RT and hope for control of tumor 20% Small volume LR after previous RT, fractionated HDR treatment may be considered.

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36 Normal Tissue Complications mean dose cochlea should be 35 Gy to reduce sensorineural hearing loss

37 Sequelae of Treatment Surgery hemorrhage, infection, loss of facial nerve function, and, rarely, carotid artery vertigo is reported after temporal bone resection, may last for 2 weeks to few permanent deafness usually occurs on the operated side

38 Sequelae of Treatment RT skin cartilage necrosis of the osteoradionecrosis of temporal bone (10% bone necrosis if RT dose > Gy, risk of necrosis increases for lesions >4 Very rarely, secondary infection and risk of brainstem and medulla oblongata