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Horses, too, can receive radiation treatments for cancer. Although
cancerous tumors such as melanomas (nodular masses) and sarcoids (skin tumors)
are more common in small animals, they can also affect larger equine species.
Fortunately, cancer in horses is treatable. There are several options.
Difficult Choices
Because of their relatively large size, horses should not be
treated with radiation therapy for tumors that may metastasize (spread). For other types of tumors, here are some forms
of radiation therapy:
- Brachytherapy
– short distance radiation
- Pleisotherapy
– very short distance radiation
- Teletherapy/External
Beam Therapy – distance radiation
- Intensity-Modulated
Radiation Therapy (IMRT) – targets tumors with correct dose; spares
normal tissue
 UC Davis Leads the
Way
With the IMRT method used at the University of California Davis,
a laser positioning system is used in conjunction with computed tomography (CT)
and magnetic resonance imaging (MRI) scans (see photo) to target the area to be
treated. Due to the concentration and
specificity of the dose, fewer treatments are required. Treatments can be
scheduled farther apart, too. Less
frequent anesthesia is preferable when treating any animal, especially a large
one that can injure itself as it struggles to rise.
UC Davis's Center for Companion Animal Health is more than a
hospital for sick pets. Its
veterinarians and scientists treat sick animals and perform research while
hoping to apply those concepts to treatments and future cures for humans. In
addition to the IMRT radiation treatment, equine drugs are tested for potential
human use.
That's a Horse of a
Different Color: Cancer in Horses
Gray horses are more predisposed to melanomas than horses of
any other color. Is this because their relatively
light-colored hair does not adequately shield their skin, or because gray
horses are genetically predisposed to cancer? I'm not sure.
Gray horses tend to develop lumpy masses known as melanomas,
which can often be benign (non-cancerous) rather than malignant (dangerous)
around their tails and faces. Surface
tumors on a horse's skin can be treated with creams or radiation. Tumors that
are relatively close to the surface can also be treated with radiation;
however, some tumors that are deep within a horse's body (including some parts
of the intestinal tract) are incurable.
Resources:
http://www.thehorse.com/ViewArticle.aspx?ID=12235&source=rss
http://www.horsetalk.co.nz/archives/2006/0607/009.shtml
http://www.horseandhound.co.uk/horsecare/1370/58078.html
http://www.ucdmc.ucdavis.edu/Synthesis/issues/winter_08/features/campus_connection.html
http://www.cvmbs.colostate.edu/development/100year_historicalfacts.cfm
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