What are eye tumors?
Eyes are organs of vision which can develop abnormal growth in many of their anatomical components. The outer layer of
the eyeball consists of the cornea and sclera (giving the eye most of its white color). The middle layer includes the iris,
ciliary body, and choroid. The choroid gives the inner eye a dark color. The inner sensory  layer includes the retina.
Abnormal growths, whether benign or malignant, can have a devastating consequence on the animal's vision and can
become life-threatening if they begin to invade into the central nervous system. The earlier the eye tumors are detected,
the better chance the pet has for saving its vision.

The following table summarizes common eye tumors in pets, their treatment and prognosis.
















Source:  Morrison Wallace B. Cancer in Dogs and Cats: Medical and Surgical Management. Baltimore: Williams&Wilkins, 1998

In the following section, we will summarize available information regarding eyelid tumors in dogs but if you want to learn
more about other eye tumors and see photographs of what these tumors look like, please click
here.

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.

Is nutritional support important 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.

Eyelid tumors in dogs
What are eyelid tumors?
An eyelid is a thin fold of skin and muscle protecting the eye which can develop both noncancerous (benign) and
cancerous (malignant) growths. Common eyelid tumors include meibomian gland adenomas and papillomas, both of which
are benign. Less common tumors include squamous cell carcinoma, melanoma, histiocytoma, mast cell tumor, and basal
cell tumor.

What are the symptoms and diagnosis of eyelid tumors in dogs?
A typical symptom of eyelid tumors is a growing mass but can be accompanied by discharge and conjunctivitis (commonly
called pink eye). Squamous cell carcinomas (SCCs) are either slightly raised masses or ulcerated areas of thickened skin.
SCCs are usually pink or red in appearance and don't respond to topical medication. The color of suspected mass,
however, does not predict its exact origin and all suspected masses should be
biopsied and sent to a pathologist (a board
certified veterinarian who specializes in diagnosing diseases) for analysis. Occasionally, eye ultrasound, skull X-rays, CT
(computed tomography), MRI (magnetic resonance imaging, chest X-rays, and lymph node
cytology are required to
evaluate the localization and extent of the disease, especially in the case of malignant tumors such as SCCs or
adenocarcinomas.

What are the treatment options for eyelid tumors in dogs?
All eyelid tumors, whether benign or malignant, have the potential to affect the dog's vision. The specific treatment of
choice will depend on the tumor type, size, location, how advanced it has become, the animal's life expectancy and
financial limitations of the owners.  In the case of young dogs affected with nonirritating papillomas or histiocytomas,
observation may be the appropriate course of treatment since spontaneous regression is common. Tumors that involve
less than one fourth to one third of the eyelid are best treated by surgical excision (removal) and tumors that involve  more
than one third of the eyelid typically require more advanced reconstructive surgery. In some cases,
chemotherapy or
radiation can be used to reduce the size of the tumor but ultimately, the treatment of choice remains surgical removal.

Cryosurgery has emerged as an attractive alternative to surgical approach and has been reported to be effective in
several eyelid tumor types. It is a quick procedure, less technically demanding, and can be performed in older or sick
animals since only a topical anesthesia or sedation is required. Swelling and temporary loss of pigmentation is usually
expected after the procedure.

What is the prognosis for dogs with eyelid tumors?
Eyelid tumors are the most common eye tumors that occur in dogs. Fortunately, the majority of them are benign (eg
meibomian gland adenomas and papillomas), and the dogs face excellent prognosis following either surgical excision or
cryosurgery. The prognosis for malignant tumors is more guarded but fortunately, the metastatic potential of these tumors
(tendency to spread to other organs) is generally very low. It is not uncommon for dogs to develop additional eyelid tumors
and these should be distinguished from recurrent tumors.

Are there any clinical trials for eye tumors in dogs?
There are no clinical trials specifically designed to treat eye tumors but there are several clinical trials available for 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).  

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

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

Sources:
  • 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.
Eye Cancer in Dogs
Cancer type
Treatment
Prognosis
Eyelid meibomian gland
adenoma
Cryosurgery or surgical
removal
Excellent
Eyelid papilloma
Surgical removal or
spontaneous remission
Excellent
Eyelid melanoma
Surgical removal
Guarded
Epibulbar melanoma
Surgical removal
Excellent
Intraocular lymphosarcoma
Chemotherapy
Guarded
Intraocular iris/ciliary body
melanoma
Eye removal
Good
Intraocular ciliary body
adenoma
Eye removal
Good
PET CANCER CENTER
Comprehensive guide to cancer diagnosis and treatment in cats and dogs
© 2007 Pet Cancer Center. ALL RIGHTS RESERVED.
Last updated 4/10/13
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