2. Tumors of the external ear most commonly occur in patients 60 to 70 years of age; tumors of the middle ear
and the mastoid are more common in patients 40 to 60 years of age.
More women than men have middle ear tumors, but more men have tumors of the external ear.
BCC >> SCC for malignancies of the external ear, but SCC accounts for 85% of EAC, middle ear, and mastoid
tumors.
For the external ear, lymphatic vessels of the tragus and anterior external portion of the auricle drain into the
superficial parotid lymph nodes. The posterior and superior aspects of the auricle drain into the retro-
auricular lymph nodes, and the lobule drains into the superficial cervical group of lymph nodes.
Lymphatics from the middle ear and the mastoid antrum pass into the parotid nodes and into the upper
deep cervical lymph nodes. The lymphatics in the middle ear and eustachian tube are rather sparse, and the
inner ear has no lymphatics.
Nodal metastases occur in <15% with lymphatic drainage to parotid > cervical > postauricular nodes.
3. T-stage AJCC staging criteria for
cutaneous carcinomas
Pittsburgh staging system for temporal bone carcinomas
T1 <2 cm in greatest dimension Limited to EAC without bony or soft-tissue extension
T2 ≥2 cm, <5 cm Limited (not full thickness) EAC bony erosion or radiographic
limited (<0.5 cm) soft-tissue involvement
T3 >5 cm Eroding osseous EAC (full thickness) with limited (<0.5 cm)
tissue involvement or tumor involving middle ear and/or
mastoid or p/w facial paralysis
T4 Invading deep extra dermal
structures (i.e., cartilage,
bone, muscle)
Eroding cochlea, petrous apex, medial wall of middle ear,
carotid canal, jugular foramen or dura, or with extensive
(> 0.5 cm) soft-tissue involvement
STAGING
No site-specific staging system is followed universally; may use histology appropriate staging.
Several proposed staging systems for EAC and middle ear; modified University of Pittsburgh system often
cited (Hirsch, Arch Otolaryngol Head Neck Surg 2002).
4. The American Joint Committee on Cancer and International Union Against Cancer
Staging System for Ear Cancer
T Category
Tx Primary tumor cannot be assessed
T0 No evidence of primary tumor
Tis Carcinoma in situ
T1 Tumor 2 cm or less in greatest dimension with fewer than two high-
risk features
T2 Tumor >2 cm in greatest dimension or tumor any size with two or
more high-risk features
T3 Tumor with invasion of maxilla, mandible, orbit, or temporal bone
T4 Tumor with invasion of skeleton (axial or appendicular) or
perineural invasion of skull base
High-risk features for the
primary tumor (T) staging
include depth of invasion
>2-mm thickness, Clark
level ≥ IV, and perineural
invasion; anatomic location
primary site on ear or hair-
bearing lip; poorly
differentiated or
undifferentiated.
5. General Management
1. External Ear
• most often treated with limited surgery or external radiation therapy.
• Treatment in early stages - megavoltage electron beam therapy or orthovoltage.
• Caccialanza et al. reported a 5-year cure rate of 78% with a mean followup of 2.4 years for 115 carcinomas of the pinna
treated with definitive kilovoltage radiation to a total dose of 45 to 70 Gy in 2.5- to 5-Gy fractions given two to three
times per week
• Surgery is beneficial if the lesion has invaded the cartilage of the ear or extends medially into the auditory canal. If
squamous cell carcinoma of the external ear is treated with surgery alone, there is a recurrence rate of 14% to 19%.
• Mohs surgery - reported local recurrence rates of 5% to 7%.
• Advanced lesions -a combination of irradiation and surgery.
• Interstitial irradiation (192Ir), particularly for tumors smaller than 4 cm, is also an effective method of treatment, excellent
local control with good cosmesis.
• Pfreundner et al. recommended a postoperative radiotherapy dose of 54 to 60 Gy for patients with negative margins.
Positive margins warrant higher doses of 66 Gy because of higher recurrence rates.
• Treatment of draining lymphatics is normally not required for early stages of external ear tumors.
• Afzelius et al. indicate that lesions >4 cm and those with cartilage invasion have an increased risk of nodal spread; they
recommend prophylactic neck dissection. Most investigators do not agree with this approach because the overall chance
of lymph node involvement in tumors of the external ear is only 16%
2. 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 to achieve, given that important structures reside around the
temporal bone. Postoperative radiation therapy is recommended
6. Surgical treatment
Appropriate margin of resection is difficult
BCC– 8mm for <3cm and 1.5mm for >3cm (Bumstead et al 1981)
2-3mm for <1cm, 3-5mm for 1-2 cm, 7-10 mm for larger tumors (scotto et al 1983)
SCC– 1-2 cm margin
Moh’s surgery
Serial horizontal section of tumor and surrounding tissues followed by immediate microscopic examination for
confirmation of margin clear or not.
Other surgical techniques are
Curretage and electro-dissection
Cryosurgery- at -40 deg C. cure rate exceeds 95%
Other Non-surgical methods- Topical 5FU in concentration of 5-20%
intralesional injection of interferon-alpha
Photodynamic therapy
7. RADIATION TECHNIQUES
Immobilization with a thermoplastic mask is necessary.
Use wax bolus to fill EAC and surrounding concha for pinna tumors to decrease complications and improve
homogeneity and superficial dose delivery.
SIMULATION AND FIELD DESIGN
• Definitive RT (usually considered for early-stage or inoperable advanced-stage pts).
• Superficial tumors of the pinna may be treated with electrons or orthovoltage photons. For small tumors, 1
cm margins are adequate, but for larger lesions, 2–3 cm margins are required.
• Advanced or unresectable EAC or middle ear tumors may be treated definitively with high energy electrons
(energy appropriate for tumor depth), or with 3DCRT/IMRT if coverage of nodal volumes is desired.
• GTV: clinical and radiographic gross disease.
• CTV1: GTV + 0.3–0.5 cm margin; 66–70 Gy at 2.0 Gy per fraction.
• CTV2: CTV1 + 0.5–0.7 cm margin, including ipsilateral preauricular and postauricular nodes, and upper level
II nodes, and parotid gland (if involved); 63 Gy at 1.8 Gy per fraction.
• CTV3 (considered for more advanced and aggressive tumors): ipsilateral level III and IV, contralateral level II;
56 Gy at 1.6 Gy per fraction.
• PTV: CTV + 0.3–0.5 cm margin.
8. Postoperative treatment.
• CTV1: original tumor, surgical bed, soft-tissue invasion, areas with possible residual disease; 60–66 Gy at 2 Gy
per fraction (62–70 Gy at 2–2.2 Gy per fraction for gross residual disease).
• CTV2: CTV1 + 0.5–0.7 cm margin, depending on anatomy include ipsilateral level II and parotid; 54–60 Gy at
1.8 Gy per fraction.
• CTV3: ipsilateral level III and IV ± contralateral level II; 50–54 Gy at 1.6 Gy per fraction.
• PTV: CTV + 0.3–0.5 cm margin.
• Care should be taken to cover the glenoid fossa of the TMJ and periauricular soft tissue as marginal misses
have been identified in these locations with IMRT
DOSE PRESCRIPTIONS
• Tumors of the pinna may be treated with 1.8–2 Gy perfraction to 50
Gy for small, thin lesions <1.5 cm, 55 Gy for larger tumors, 60 Gy for
minimal or suspected cartilage or bone invasion, or 65 Gy for large
lesions with bone or cartilage invasion.
• Tumors of the auditory canal or temporal bone: postoperative, 54–
66 Gy; definitive, 66–70 Gy, and may consider chemo-RT.
9. 2D planning technique
1. Assessment of primary disease- examination of ear,
parotid, mastoid region, LN, post nasal space, and
cranial nerve examination.
2. Definition of target volume- anterior and posterior
limits are defined by the pre and post auricular
nodes and the mastoid process. Upper border
below the eye and the lower border extends to the
tip of the mastoid
In transverse section the volume is triangular with tip of
the apex just anterior to the brain stem.
3. localization- supine position, cast is made with the
neck well extended to obtain a vertical line through
the top of the pinna and the floor of the orbit. This
avoids dose to the eye and keeps the treatment
plane perpendicular to the couch.
Lateral and AP simulator films are taken, and volume of
spinal cord or brainstem are localized
10. 4. Field arrangements- anterior and posterior
wedged field are used to cover the triangular
volume. The posterior oblique field exist below the
eye and dose to the contralateral eye can be
checked.
5. Dose prescription-
66 Gy in 33 # over 6.5 weeks.
Alternative regimen
55 Gy in 20 # over 4 weeks.
11. Normal Tissue Dose Constraints
Structure Constraints
Brainstem Maximum <60 Gy
Spinal cord Maximum <45 Gy
Cochlea Mean dose <45 Gy
Optic nerve Maximum <55 Gy
Optic chiasm Maximum <55 Gy
Lens Maximum <45 Gy
Larynx Mean dose <44 Gy; maximum <66 Gy
Oral Cavity Mean dose <35 Gy
Parotid gland Combined parotid glands mean dose <25 Gy or spare
one
parotid gland mean dose <20 Gy
Temporal bone Limit to <70 Gy to reduce osteoradionecrosis chance
12. SEQUELAE OF TREATMENT
POSSIBLE SEQUELAE WITH SURGERY ARE
• HEMORRHAGE,
• INFECTION,
• LOSS OF FACIAL NERVE FUNCTION, AND,
• RARELY, CAROTID ARTERY THROMBOSIS.
• OCCASIONALLY, VERTIGO IS REPORTED AFTER TEMPORAL BONE RESECTION
• PERMANENT DEAFNESS USUALLY OCCURS ON THE OPERATED SIDE.
RADIATION THERAPY SEQUELAE INCLUDE
• CARTILAGE NECROSIS OF THE EXTERNAL AUDITORY CANAL AND
• OSTEORADIONECROSIS OF TEMPORAL BONE.
• VERY RARELY, SECONDARY INFECTION AND MENINGITIS ARE REPORTED
• AN OVERALL 10% INCIDENCE OF BONE
• NECROSIS CAN BE EXPECTED AFTER ADMINISTRATION OF 60 TO 65 GY.
• AFTER EXTERNAL EAR LESIONS ARE TREATED WITH INTERSTITIAL IRRADIATION, THERE IS A 4% INCIDENCE OF LATE CUTANEOUS AND CARTILAGE
NECROSIS.
• RISK OF NECROSIS INCREASES FOR LESIONS >4 CM
• ACUTE GRADE 2 AND 3 SKIN TOXICITIES WITH POSTOPERATIVE IMRT
• 30% INCIDENCE OF XEROSTOMIA.
