Site:
Ear and Temporal Bone
Histology:
Squamous Cell Carcinoma,Basal Cell Carcinoma,Adenoid Cystic Carcinoma
Stage:
Lesions Involving External Auditory Canal and/or Bone 
  1. DIAGNOSTIC EVALUATION
  2. EXAMINATION UNDER ANESTHESIA AND BIOPSY
  3. TREATMENT
  4. POSTOPERATIVE IRRADIATION
  5. FOLLOW UP
  6. BIBLIOGRAPHY

I. DIAGNOSTIC EVALUATION:

Clinical Evaluation:

  • Complete history and physical examination
  • Complete examination of the head and neck

    Includes complete inspection of both ears; evaluation of hearing with tuning forks; examination of the nose, oral cavity, pharynx and larynx; palpation of the neck; and evaluation of facial nerve function.
  • Biopsy of primary
  • Bilateral comprehensive hearing evaluation

Imaging Studies:

  • Radiographs of the chest, PA and lateral

    To assess for metastases, a second primary cancer, acute or chronic pulmonary disease.

  • A CAT scan or MRI of the temporal bones and neck

    To assess for extent of the primary tumor; its relationship to the dura, brain tissue, facial nerve, and carotid artery; and for cervical metastases. 

Laboratory Tests:
  • Pre anesthesia evaluation as per institutional guidelines
  • Liver enzymes (Alkaline phosphatase, SGOT, SGPT)
Consultations:
  • Neurosurgery Consult

    When needed to assist in skull base surgery procedure.

  • Reconstructive surgery consult

    When complex reconstruction is anticipated because of major soft tissue deformity, especially when dural resection and/or carotid artery exposure is anticipated.

  • Radiation oncology consultation

    In anticipation possible of definitive or post operative radiation.

  • Internal Medicine, Cardiology or Anesthesiology

    As needed to evaluate coexisting conditions that may preclude or increase the risk of general anesthesia, or may influence therapeutic decisions.

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II. EXAMINATION UNDER ANESTHESIA AND BIOPSY:

Occasionally necessary in cases where it is difficult to obtain adequate tissue for diagnosis under local anesthesia.

III. TREATMENT:

Primary tumor:

Complete surgical resection with clear microscopic margins is preferred in patients with resectable cancers, if consistent with a reasonable functional outcome and perioperative morbidity. For small tumors, radiation therapy is a good alternative. Resection frequently requires a surgical team consisting of a head and neck surgeon, a neurotologist and a neurosurgeon. A lateral temporal bone resection may be appropriate when the tumor approaches the temporal bone but the aerated spaces of the middle ear and mastoid are not involved; otherwise a subtotal resection of the temporal bone may be necessary. The facial nerve is generally sacrificed when the middle ear or mastoid air spaces are involved or if the nerve is dysfunctional.

Involvement of the brain or the internal carotid artery may signify an unresectable cancer. In those cases radiation therapy is occasionally curative, particularly for basal cell carcinomas.

Neck:

N0: Ipsilateral upper neck dissection (level 2 and 3 nodes) to aid in resection of the primary tumor and clear the first echelon of nodes.

N1: Modified radical neck dissection with preservation of the spinal accessory nerve, sternocleidomastoid muscle and internal jugular vein when possible.

N2,3: Ipsilateral radical neck dissection or modified neck dissection with preservation of the spinal accessory nerve, sternocleidomastoid muscle and jugular vein when possible.

Reconstruction:

Primary closure with closure of the external auditory canal and eustachian tube is appropriate when the pinna and its blood supply are preserved. Obliteration of dead space may require a temporalis muscle flap or a free fat graft.

Closure with a scalp flap or regional myocutaneous flap may be appropriate in selected patients with major soft tissue deformities, but free tissue transfer with microvascular anastomosis may be preferable especially when deep deformities would leave dead space, and after dural repair.

The sacrificed facial nerve may be grafted when proximal and distal microscopic margins are clear. Suspension of remaining facial muscles with fasciae may be helpful when the facial nerve cannot be grafted.

The surgical treatment includes:

  • Frozen section evaluation of soft tissue margins as needed to ensure adequate resection. br />
  • Insertion of drains
  • Orientation of the specimen for the pathologist, by the surgeon

Postoperative care includes:

  • Hospitalization for 3-14 days
  • Perioperative antibiotics
  • Low pressure suction to drains
  • Removal of suction drains when output is <30-50 ml/day
  • Careful observation of the wound for evidence of bleeding, CSF leak or flap necrosis 

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IV. POSTOPERATIVE IRRADIATION:

Indications:

Postoperative irradiation is indicated when the extent of the primary tumor is such that resection margins are close (less than 5 mm), when proximity of the tumor to important structures such as the carotid or the facial nerve preclude a resection with "wide" margins, when the margins of resection are microscopically positive and when there is perineural invasion. It is generally indicated in cases of adenoid cystic carcinoma. It is also indicated when there are multiple histologically positive nodes or there is extracapsular extension of tumor. A baseline postoperative CT or MRI scan is required prior to radiation therapy. 

Timing: 

Radiation is initiated within a reasonable period after healing has occurred. 

Total dose and fractionation:

These are determined by the clinical and pathological findings. The usual range is 50 - 70 Gy in daily fractions of 1.8 to 2.0 Gy in 5 to 8 weeks. This include a brachytherapy boost when indicated by pathological findings such as unsatisfactory margins. Irradiation to the neck is indicated if neck dissection reveals more than minimal metastatic disease.

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V. FOLLOW UP:

Follow-up appointments are scheduled on an individual basis determined by the risk of recurrence, to deal with morbidity from treatment (i.e. wound care), to provide social and psychological support, and to deal with comorbidity not directly related to the cancer itself.

  • Periodic examinations by the head and neck surgeon may be necessary during radiation therapy in patients experiencing difficulty with nutritional intake, airway or pain control.

  • Periodic examinations by the radiation oncologist and a dentist in patients that received radiation therapy

  • After all treatment is completed a general formula which is modified according to the individual patient's characteristics is:

    • 1st year post treatment: 1-3 months

    2nd year post treatment: 2-4 months

    3rd year post treatment: 3-6 months

    4th and 5th years: 4-6 months

    After 5 years: Every 12 months

  • Chest radiographs, yearly
  • Liver enzymes, yearly

  • Thyroid function tests should be monitored if the patient received radiation to the lower neck. These studies should be repeated according to clinical findings on follow-up examinations

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VI. BIBLIOGRAPHY:

Afzelius AE, Gunnarsson M, Nordgren H: Guidelines for prophylactic radical lymph node dissection in cases of carcinoma of the external ear. Head Neck Surg 2:361, 1980.

Arriaga, M., Curtin, H., Takahashi, H., et al: "Staging Proposal for External Auditory Meatus Carcinoma Based on Preoperative Clinical Examination and Computed Tomography Findings", Annals of Otology, Rhinology, and Laryngology, 1990; 99(9.1): 714-721. 

Austin JR, Stewart KL, Fawzi N: Squamous cell carcinoma of the external auditory canal: Therapeutic prognosis based on a proposed staging system. Arch Otolaryngol 120:1228, 1994.

Goodwin WJ, Jesse RH: Malignant neoplasms of the external auditory canal and temporal bone. Arch Otolaryngol 106: 675, 1980.

Medina JE, Park AO, Neely JG, Britton BH. Lateral Temporal Bone Resections. Amer J Surgery, 160:427-433, 1990.

Schockley WW, Stucker FJ: Squamous cell carcinoma of the external ear: A review of 75 cases. Oto Head Neck Surg. 97:308,1987.