Cancers of the ear

Clinical picture

There are three parts to the ear. These are the outer, middle and inner ear. Although rare, cancer can affect all of these parts. When a malignant uncontrolled growth of cells occurs in the inner ear or in the external auditory canal, it is known as cancer of the ear. Cancer on the shell of the ear is usually classified as a type of skin cancer.

Cancers of the ear are rare: of all the tumours in the head-neck area, only 0.2% are cancers of the ear.

Outer ear: The outer ear consists in itself of three parts: the shell, the auditory canal and the tympanum or eardrum. The auditory canal contains glands that produce ear wax, which protects the inner ear against dust and insects.
Middle ear: This part of the ear contains the ossicles, three of the smallest bones in the human body: malleus, incus, and stapes. These bones transfer sounds from the middle ear towards the inner ear and the auditory nerve.
Inner ear: The cochlea, the aural nerve and the balance organ are all found in the inner ear. The cochlea translates vibrations into electronic impulses that are transmitted to the brain by the auditory nerve. The balance organ consists of the semi-circular ducts and several smaller parts.

Cancers of the ear are mostly defined by their location.

Basal cell carcinoma: the most common type of cancer of the ear, growing on the epidermis.
Adenoid cystic or adenocarcinoma: a tumour in the glands. These tumours produce mucous and are generally slow-growing.
Ceruminoma: a tumour in the cells that produces ear wax.
Sarcoma: malignant growth in the connective tissue.
Metastases from cancer elsewhere in the body.

Symptoms

The symptoms of ear cancer depend on the tumour location.

Ear canal: pain, discharge from the ear, loss of hearing, a lump in the ear canal, difficulty with producing facial expressions.
Middle ear: the most common symptom is a discharge from the ear, which may be blood stained. Other symptoms include hearing loss, earache, partial paralysis of the face on the side of the affected ear.
Inner ear: pain, headache, hearing loss, tinnitus, dizziness. Some people with ear cancer might also have swollen lymph nodes in their neck.

Cause

The cause of ear cancer is largely unknown. People with a history of chronic ear infections have a higher risk of developing cancer in the middle ear.

Diagnosis

The only way to confirm a diagnosis of ear cancer is for an ear-nose-throat specialist to remove a small amount of tissue (biopsy) from the affected area of the ear. A pathologist then examines this under a microscope. Biopsies of the middle ear can be difficult. So in this situation, a patient might have a general anaesthetic instead. Doctors do not take biopsies of the inner ear, because it is very difficult to reach without causing problems to other structures around it. The doctor will make a diagnosis using MRI scans and CT scans. If the biopsy shows up positive for cancer, further tests also include an MRI scan or CT scan that help the doctors to decide on a treatment.

There are different staging systems for cancer of the ear, following the TNM system. T describes the size of the tumour, N describes whether there are any cancer cells in the lymph nodes and M describes whether the cancer has spread to a different part of the body.

The T staging for the ear canal and the middle ear is:

T1: the tumour is only situated in the middle ear and is not causing any numbness of the face and is not situated in the nearby bone.
T2: the tumour has grown outside the area and is causing numbness or is affecting the bone.
T3: the tumour has grown into the nearby salivary gland (parotid gland), the base of the skull or the joint of the jaw.

Treatment

If the cancer is detected at an early stage, it can often be removed through surgery. Radiation therapy can serve as an adjuvant therapy, but can also be the sole form of treatment if surgery is not an option due to the location of the tumour or the stage it is in. Chemotherapy is only prescribed as part of palliative care, when healing is no longer an option and where pain relief is the main objective.