Ear Cancer in Cats

Ear canal tumors are most often found in the external ear canal and the outer ear. In rare cases, tumors can occur in the inner or middle ear. Prompt diagnosis and treatment is critical for the cat’s survival.

Two primary forms of cancer that affect the ears of cats are squamous cell carcinoma and ear canal tumors. Squamous cell carcinoma most commonly presents as a red, crusty areas around the pinna of the ears. The sores, or ulcers, may occur intermittently and are usually flat, irregularly shaped and scaly. If the sores are noticed early enough and proper treatment is administered the prognosis is generally good. Unfortunately, the carcinoma can reoccur after removal and may metastasize to other areas of the body. 

The primary symptom of squamous cell carcinoma is the presence of bleeding ulcers on the pinna of the  ears. In advanced stages, the tips of the ears may disappear, leaving a noticeable deformity.

Ear canal tumors usually cause symptoms on one side of the head only. Owners should look or the presence of one or more of the following:

• Ear discharge (may be waxy, pus-filled, or bloody) 
• Foul odor
• Head shaking
• Ear scratching
• Swelling
• Draining abscess below affected ear
• Deafness

When tumors are located in the inner ear, affected cats may present additional symptoms including:

• Loss of balance
• Difficulty blinking
• Other neurological problems or coordination 
• Head tilt

Squamous cell carcinoma is most often caused by ultraviolet (UV) damage from excess sun exposure. It is most common in white cats with white ears. In rare cases, the condition can develop following severe burn damage. It is possible for squamous cell carcinoma to affect dark-colored cats or develop on areas that are covered by fur. This is the result of a disorder called Bowen’s disease that may be associated with the presence of a virus.

Tumors in the ear canal have not been definitively connected to a specific cause. Ongoing ear canal inflammation may cause the growth of abnormal cells that can develop into tumors. Cats with a history of ear infections tend to be more prone to this condition. Middle-aged or older cats are more likely to be affected than younger cats, and the tumors are more likely to be malignant than benign.

The first step will be a full review of the cat’s medical history. Owners should make the vet aware of any sores that the cat has had in the recent past, even if other factors are thought to be to blame. The vet will perform a thorough physical exam to look for other sores on the body and will likely order common lab tests like a complete blood count (CBC), biochemistry profile, urinalysis, and electrolyte panel. Enlarged lymph nodes or a high white blood cell count may indicate the presence of an infection or cancer that has spread. Chest and skull x-rays may be performed to check for tumors or other abnormalities. A biopsy can be performed to determine whether the tumor is a carcinoma, benign mass, or other skin condition. This is often done as a last resort as it typically requires general anesthesia.

If an inner-ear tumor is suspected, the vet may sedate the cat and complete a deep otoscopic examination. Other diagnostic methods may include CT scan, MRI, and biopsy. 

Treatment recommendations will depend on the type of cancer, the size of the ulcers or tumor, and whether it has spread.

Treatment of Squamous Cell Carcinoma 

If only one small ulcer is present, the vet may freeze and remove it using cryosurgery. If the ulcer is large or multiple sores are present, traditional surgery will be required. The external area of the cat’s ear, called the pinna, is usually removed. In some cases, a portion of the ear canal may be removed as well. Cats are usually able to adapt to the change and heal fairly well following surgery. Chemotherapy is less effective than surgery, but may be recommended in cases where surgical removal is not an option. The vet may recommend a consultation with a veterinary cancer specialist for further treatment recommendations.

Treatment of Ear Canal Tumors 

When ear canal tumors are present, surgical removal is required. This is best performed by a board-certified surgical specialist, especially when the inner-ear is involved. The most common surgery is known as a total ear canal ablation (TECA). It involves the removal of the entire ear canal and a thorough cleaning of the inner ear. When surgery fails to remove the entire tumor, radiation may be used to slow tumor growth and minimize pain.

Cats with squamous cell carcinoma should be kept indoors and out of the sun as much as possible. If the cat must be outside in the daytime, sunscreen should be applied to the ears and nose. For cats that enjoy sitting on windowsills, the addition of a reflector or shade will help to block UV rays. Owners should watch closely for the outbreak of new sores and follow up with a veterinarian if reoccurrence is suspected. If the treatment was administered quickly enough and the cancer has not spread, prognosis for cats with squamous cell carcinoma is generally positive.

Cats with ear canal tumors usually survive for about a year following aggressive surgery. If more conservative treatment options are elected, prognosis worsens significantly. Throughout the remainder of the cat’s life, regular veterinary check-ups will be necessary.