Cure for Equine Eye Cancer

Like human cancers, animal cancers can often be difficult to diagnose and even harder to treat. Equine cancers can be particularly hard to diagnose due to the horse's innate stoicism and reluctance to show pain. Often symptoms will not display themselves until the disease is far advanced. Eye cancers, in particular, often mimic the symptoms of other diseases such as glaucoma or uveitis, and defy diagnoses.

  1. Causes

    • While not much is known about what causes any particular kind of neoplasia, eye cancer in horses is related to predisposition and environment. Gray or light-colored horses have been shown to have a higher risk of developing this disease, and older horses are also more susceptible. Exposure to high-altitude ultraviolet light and frequent sun exposure has also shown to be a component, much as in skin melanomas in humans.

    Types

    • The most common form of eye cancer in horses is squamous cell carcinoma, a neoplasia of the soft tissues of the body. This type of cancer is often metastatic and needs aggressive treatment. It can quickly spread to other organs of the body and can be considered life-threatening.

    Symptoms

    • Although eye cancer is more prevalent in gray or light-skinned horses, any breed of horse can be diagnosed with it. Paint, Belgian and Appaloosas are more likely to develop this disease due to the lighter coloring around their eyes. Small, fleshy tumors can form on the outer eyelids, the third eyelid, behind the orbital wall and in the eye itself. Sometimes a darkening of the cornea or fogging of the iris may occur. The eyeball may become swollen and painful, with excessive blinking and discharge, and the horse may show signs of blindness in that eye.

    Treatments

    • Treatment of equine eye cancer depends on the size and location of the tumor. Usually surgical removal and debridement of the tumor is the first step, but often total removal of the eyeball (enucleation) is recommended. Chemotherapy agents such as Cisplatin or 5-flouracil may be injected into the tumor if it is located on the lid or around the eye. Surgical lasers can be used to remove a majority of the affected structures with Cisplatin beads placed in the surrounding tissue. Some equine hospitals are also using radiation therapy to treat these tumors but this usually occurs after enucleation of the eyeball. This type of therapy may also increase the life span of the animal.

    Considerations

    • The cost of these various cancer treatments, plus transportation and boarding at equine medical facilities, can be prohibitive for many horse owners and must be taken into consideration when considering options. The extent of the disease, whether it has remained localized or spread to other organs, is another consideration. The age and general body condition of the horse must also be looked at, as elderly and debilitated patients are much less likely to recover from surgery. An owner must also take into account whether they are physically and emotionally able to care for a partially blind animal.

    Warning

    • When the treatment fails to be curative, supportive care must be undertaken using painkillers and anti-inflammatory medications. Even with aggressive treatment, some studies have shown that over two-thirds of horses with eye cancer will be euthanized within five years of diagnoses due to recurrence of the tumor, mestasis, or complications of the tumor.