A Mare Defies the Odds in Her Battle with Cancer - The Horse Owner's Resource

A Mare Defies the Odds in Her Battle with Cancer

A mare manages to defy the odds, not once, but twice after cancer diagnosis. By Tom Moates for EQUUS magazine.
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At 24, Q.T. could take on horses half her age going around barrels. The aptly named gray Quarter Horse--Q.T. stood for Quick Turns--had been purchased by the Hollond family of Emporia, Kansas, three years before, and she had excelled at barrel racing ever since.

©Practical Horseman. All Rights Reserved.

©Practical Horseman. All Rights Reserved.

In fact, she had carried the two Hollond daughters, Lindsey and Taylor, to victories in local competition that brought them each a trophy saddle.

Then one afternoon, Kim Hollond noticed that Q.T.'s right eye was nearly swollen shut. When Kim gently pried the eyelids apart, she could see that the eyeball itself looked a bit milky. She immediately called the family's regular veterinarian, Alan Lewis, DVM.

When Lewis arrived, he carefully examined the eye and noticed a striking abnormality. "There was clearly a growth in the third eyelid," he recalls. Technically known as the nictitating membrane, the third eyelid is a thick fold of tissue that lies flat on the inner corner of the horse's cornea.

Lewis consulted with Alan Brightman, DVM, a board-certified veterinary ophthalmologist at Kansas State University. Given the mare's age and general good health, the two veterinarians decided to start with conservative treatment. They prescribed a topical steroid/antibiotic gel to try to shrink or eliminate the mass.

The gel, which was applied to the affected eye twice a day, seemed to do the trick at first: The mass got smaller and the eyelid swelling nearly disappeared. But each time the treatment was stopped, the mass returned and Q.T.'s eye would swell shut again.

After five weeks of improvements and relapses, the Hollonds decided to ship the mare to Kansas State University Veterinary Medical Teaching Hospital in Manhattan.

A Surgical Solution
At the hospital, Brightman evaluated Q.T.'s eye and confirmed Lewis's findings. He then conducted further tests on both eyes and determined that the mare's vision and intraocular pressure, as well as her pupils' reflexive responses to light, were normal. The strange mass was the only thing wrong with Q.T.

The next step, said Brightman, was surgery. Although the nictitating membrane helps cleanse, moisten and protect the eye, Q.T. could get by without it, he explained.

The removal procedure would not be difficult, said Brightman, but it would require that Q.T. undergo general anesthesia. The Hollonds had some reservations about putting their old mare through the rigors of surgery but decided it was worth the risk.

Brightman removed the entire right nictitating membrane, closing the incision on the conjunctiva with tiny stitches. Q.T. recovered from surgery uneventfully, and the mass was sent to the pathology laboratory for analysis.

Two days later, the results came back. They indicated a mixed prognosis. As the veterinarians suspected, the lump contained squamous cell carcinoma, the most common cause of eyelid tumors. Usually found in horses with light skin, squamous cell carcinoma tumors typically do not spread.

More troubling, however, was the presence in the mass of mixed cell lymphosarcoma. Brightman told the Hollonds that this rare condition is usually the result of systemic lymphosarcoma, meaning a cancer has already spread throughout the body.

But to everyone's surprise and relief, the pathology report showed that Q.T.'s lymphosarcoma tumor appeared to be the exception: Careful examination of the removed tissue revealed that the abnormal cells seemed to be restricted to the mass itself and removal of the entire membrane appeared to have fully eliminated the cancer, said Brightman.

However, the possibility remained that the cancer had spread to the regional lymph nodes undetected and from there moved to other areas. Q.T. was given a guarded prognosis.

The Cancer Returns
Q.T. recovered from the surgery and resumed her barrel racing career, carrying the Hollond girls to several more victories.

Then one morning a year and a half after her surgery, Q.T. developed another ominous swelling--this time in her left eye. A few days later, a tumor clearly was visible on the nictitating membrane. Fairly certain of what they were dealing with, the Hollonds shipped Q.T. straight to Kansas State University Hospital, where Brightman was awaiting their arrival with Jennifer D'Agostino, DVM, a small animal intern spending time on the ophthalmology rotation.

D'Agostino examined Q.T.'s eye, a task she remembers as being particularly challenging. "It was very difficult to evaluate the [eyeball] because the mass was so large--about the size of a walnut." As before, Q.T. had normal vision, pressure and reflexes in the affected eye. Once again, Brightman decided that the best course of action was to remove the nictitating membrane.

Q.T.'s second surgery went well, but as the team awaited the results of the laboratory analysis, a troubling question lingered. If the second tumor was indeed a lymphosarcoma, was it a sign that the cancer had spread throughout Q.T.'s body? The fact that the mare had no systemic cancer when the first tumor was discovered had surprised every expert involved in the case--a situation that has been reported only a few times in veterinary literature. Could the mare have had two occurrences of lymphosarcoma that hadn't spread beyond their original sites?

The pathology report brought good news. The mass was a lymphosarcoma, but, as before, it appeared that the cancer had not spread. Why Q.T. had developed two separate lymphosarcomas of the nictitating membrane was--and still is--a mystery.

Of course, the Hollonds didn't need an explanation to appreciate how lucky they were to have Q.T. healthy and back at home. After a brief course of topical antibiotics, the mare resumed her usual routine and spent the next two years in good health.

When, at age 28, Q.T. developed a lump on her muzzle, the thought crossed everyone's mind that it could be lymphosarcoma. Lewis, however, believed that the new growth was probably a totally new type of cancer.

It hardly mattered to the Hollonds, who decided that they didn't want to put their aged mare through any aggressive treatments. Instead they would let Q.T. live out her days roaming her pasture until she became uncomfortable. When that time came, they would humanely end her life.

In the seven years Q.T. spent with the Hollond family, she had been a kind teacher, keen competitor and trusted friend. And the mare made one final gift to the family: She spared them from having to make the difficult decision about euthanasia. Q.T. passed away peacefully in her pasture before her health had obviously declined.

This article originally appeared in the September 2005 issue of EQUUS magazine.

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