Management of Malignant Tumors that Invade the Temporal Bone

Very large tumors, whether originating in the skin, parotid gland, or ear canal, might be considered for preoperative chemotherapy. They are also frequently treated with postoperative radiation, Dr. Gidley said.

Postoperative radiation is also used when the primary tumor has surgical margins less than 5 mm or if the tumor is too close to the carotid artery or facial nerve to allow wide surgical margins, when the margins are microscopically positive, and if there is perineural invasion. Radiation is also used in most cases of adenoid cystic carcinoma and when there are multiple positive nodes or extracapsular extension of tumor.

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Figure. Type IV: Lateral temporal bone resection

Effects of Surgery

Postoperative radiotherapy can cause dry mouth. Surgery may cause paralysis of the facial nerve. Lateral temporal bone resection involves removal of the bony ear canal, tympanic membrane, and the small bones inside the ear, which destroys sound conductivity but preserves inner ear hearing, Dr. Gidley explained.

“Patients treated with lateral temporal bone resection have maximum conductive hearing loss. We can measure hearing in different ways to find the site of hearing loss. Older people usually have some degree of inner ear hearing loss, while those who undergo this type of surgery will have impaired conduction of sound,” he said.

Postoperative care includes hospitalization (possibly for up to two weeks), perioperative antibiotics, suction drains until output is less than 30 to 50 mL/day, and careful observation of the surgical wound for evidence of bleeding, cerebrospinal fluid leak, or flap necrosis.

Follow-up care depends on the extent of the surgery and the risk of recurrence. Appointments with the surgeon, radiation oncologist, and dentist are made on an individualized basis. In general, patients are seen anywhere from every month to every three months during the first year postsurgery, with longer intervals between appointments with each progressive year. By the fourth and fifth year after surgery, patients are usually seen every four or six months, and after five years they can be seen annually. All patients with malignant tumors should have annual chest X-rays and liver enzyme tests. Thyroid function tests are needed for patients whose lower neck received radiation.

Prognosis

Patients with stage IV tumors arising from the skin and parotid gland that invade the temporal bone tend to have a worse prognosis than those with smaller tumors arising from these sites. The average five-year survival rate is about 40%, Dr. Gidley said. Primary tumors of the temporal bone that are confined to the ear canal have a five-year survival of 80% to 100%, but if the tumor invades the mastoid bone or the inner ear, five-year survival drops to between 30% and 50%.