The most common benign tumors in both cats and dogs are inflammatory polyps, papillomas, basal cell tumors, and
ceruminous gland adenomas (tumors of glands producing earwax).

How common are ear tumors in cats and dogs?
The average age for the development of benign ear tumors is 7 years for cats and 9 years for dogs. The average age for
the development of malignant ear tumors is 11 years for both cats and dogs. The cocker spaniel appears to be at higher
risk for both benign and malignant tumors which may be related to their elevated risk of chronic ear inflammations.

Ceruminous gland cyst (cyst of earwax producing glan) is a common tumor-like lesion that occurs in cats which  appear as
purple or black masses containing an oily black fluid. They can be often multiple and be mistaken for melanomas of basal
cell carcinomas. The most common malignant ear tumor in dogs is called ceruminous gland adenocarcinoma, followed by
squamous cell carcinoma and carcinoma of unknown origin. Other types of ear tumors have been reported but these occur
at much lower frequency.

What are the symptoms of ear tumors in cats and dogs?
The most common observed symptom of ear tumors is the presence of a mass, discharge, odor, itchiness, and local pain.
Neurological signs are observed in approximately 10% of dogs with malignant tumors and 25% of cats with either benign or
malignant tumors. Benign tumors are typically raised masses which are rarely ulcerated in contrast to malignant tumors
which are more likely to be ulcerated and bleeding.

How is the diagnosis made?
Every skin tumor should be first examined for size, location, ulceration and whether it is freely movable or fixed to
underlying. However, in order to determine the exact nature of the mass, either cytologic or histopathologic analysis of the
mass should be done in order to design an appropriate treatment strategy and predict the pet's prognosis. The commonly
used diagnostic procedures for skin tumors are
fine-needle aspiration cytology and tissue biopsy. Cytology is an important
tool that can help the veterinarian distinguish a tumor from inflammatory lesions and to evaluate whether the present mass
spread to the lymph nodes but only
histopathoogic examination of the tumor can definitively establish the tumor's type,
grade (level of aggressiveness), what treatment is most appropriate and prognosis about future behavior. The biopsy
technique used will largely depend on the tumor's size and location. Small masses are usually completely excised and sent
to the pathology lab to confirm that the surrounding healthy tissues that were excised along with the tumor do not contain
any cancer cells (indicating successful tumor removal). If the tumor is larger, a small sample is removed for analysis and
depending on the results, appropriate treatment is chosen. Depending on the tumor type and its known level of
aggressiveness, additional diagnostic tests can include blood tests to assess the overall health of the pet, chest X-rays to
check for lung metastasis, and abdominal ultrasound to check for metastasis to other internal organs (eg liver, spleen).
Advanced imaging such as CT (computed tomography) or MRI (magnetic resonance imaging) can be very useful in
evaluating the extent of the pet's disease but, unfortunately, are not readily available in every area.

Does cancer cause pain in pets?
Pain is common in pets with cancer, with some tumors causing more pain than others. In addition to pain caused by the
actual tumors, pets will also experience pain associated with cancer treatments such as surgery, radiation therapy or
chemotherapy. Untreated pain decreases the pet's quality of life, and prolongs recovery from the illness, treatment or
injury. It is, therefore, essential that veterinary teams that are taking care of pets with cancer should also play a vital role in
educating pet owners about recognizing and managing pain in their pets. The best way to manage cancer pain in pets is to
prevent it, a term referred to as preemptive pain management. This strategy anticipates pain ahead of time and
administers pain medication before the pet actually experiences pain, thus ensuring the pet's maximum comfort.

To learn more about which tumors are likely to cause a lot of pain, how to recognize pain in pets with cancer and what
cancer pain management options are available for your pet, please visit the
Cancer Pain Management section.

How important is nutritional support for pets with cancer?
Cancer cachexia (a term referring to progressive severe weight loss) is frequently observed in pets with cancer. Pets with
cancer lose weight partly because of lack of appetite and partly because of cancer-induced altered metabolism. Some of
the causes for decreased appetite are related to the cancer itself (for example, tumors may physically interfere with food
chewing, swallowing, and digestion process) and some may be related to the side effects of cancer treatment (for example,
some chemotherapy drugs cause nausea and vomiting, and radiation therapy can cause mouth inflammation).

Proper nutrition while undergoing cancer treatment is essential to maintain your pet's strength, improve survival times,
quality of life and maximize response to therapy. Adequate nutritional support was shown to decrease the duration of
hospitalization, reduce post-surgery complications and enhance the healing process. Additionally, pets with cancer need to
be fed diets specifically designed to provide maximum benefit and nutritional support for the patient. To learn more, please
visit the
Cancer Nutrition section.

What are the treatment options for ear tumors in cats and dogs?
Ear tumors are almost exclusively treated by surgical removal. (For a review of ear surgery, its benefits and potential
complications, please click
here). Most benign ear tumors are easily surgically removed but more aggressive tumor types
typically require more aggressive surgery to control the tumor and improve survival. Dogs whose invasive ear tumors were
treated by aggressive surgery had a median survival of 36 months compared to 9 months in those treated with
conservative surgery.
Radiation therapy is a viable alternative to surgery  or can be used in addition to surgery when the
entire ear tumor could not be surgically removed. One study showed that the 1-year median survival for dogs and cats
treated by radiation therapy after incomplete surgery for ceruminous gland adenocarcinoma was 56%.
therapy has been suggested as an additional treatment but no available data exist to support its benefit. The use of
chemotherapy has not been evaluated in ear tumors in cats and dogs.

How do I find a qualified veterinary oncologist?
To locate a qualified veterinary oncologist in your area who can discuss with you appropriate cancer treatment plan for
your pet's cancer condition, please visit the "
Locate a veterinary oncologist" section.  

Are there any clinical trials investigating new treatments for ear tumors in dogs or cats?
There are no available clinical trials investigating new treatments specifically for ear tumors in pets, but there are several
clinical trials available for cats and dogs with any tumor type for which your pet may qualify. To learn more these trials
(which are partially or fully funded by the institutions), please visit the
Dog Clinical Trials (any tumor type) or Cat Clinical
Trials (any tumor type) section.  

To learn more about veterinary clinical trials in general, please visit the
Pet Clinical Trials section.

What is the prognosis for cats and dogs with ear tumors?
Malignant ear tumors are less aggressive in dogs than in cats. Available data suggest that most dogs live longer than 2
years after initial diagnosis whereas the median survival time for cats is only 1 year. Ear tumors are typically only locally
invasive and rarely metastasize (spread) to other organs in the pet's body. Approximately 10% of dogs and 5-15% of cats
have shown tumor's spread to regional lymph nodes or the lungs. Cats with squamous cell carcinoma of the ear canal
rather than the ear tip are more likely to experience neurological signs, indicative of the tumor's invasive behavior and
worse prognosis. In case of cat ceruminous gland adenocarcinoma, the estimated 1 year survival is 75% following
aggressive treatment compared to 33% following more conservative surgery.

Additional online resources about skin cancer in pets

  • Withrow Stephen J, and David M. Vail. Small Animal Clinical Oncology. St Louis: Saunders Elsevier, 2007.
  • Morrison Wallace B. Cancer in Dogs and Cats: Medical and Surgical Management. Baltimore: Williams&Wilkins, 1998.
Ear Canal Tumors in Cats and Dogs
© 2007 Pet Cancer Center. ALL RIGHTS RESERVED.
Last updated 2/19/2017
Comprehensive guide to cancer diagnosis and treatment in cats and dogs