Cornell University Hospital for Animals


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Vision for the future

When cancer first emerged to threaten her sight, Mariclare didn’t like people. The huge Belgian horse spent her first 12 years in an abusive situation, severely confined and destined for slaughter.

She escaped that fate when she was bought by Susan Wagner, president of Equine Advocates Rescue and Sanctuary, embarking on a new life at the group’s sanctuary near Chatham, N.Y.

“At first Mariclare was very difficult,” said Wagner. “She hated being handled. She was afraid of everything and everyone.”

But in 2007, Wagner got close enough to notice something wrong with her left eye. Her local veterinarian suspected squamous cell carcinoma (SCC), a kind of malignant tumor common in Belgians. Wagner began treating Mariclare at home with mitomycin, an anti-tumor ointment. At first the growth shrank, but later started rapidly expanding. So Wagner drove the struggling 1600-lb horse to the Cornell University Hospital for Animals for surgical treatment.

“She was terrified and her left eye looked dreadful,” said Dr. Nita Irby, large-animal ophthalmologist. “We found two large masses so extensive they couldn’t be removed without losing the eye.”

Mariclare’s situation darkened further when Dr. Irby found more suspicious areas in her right eye. One raised cauliflower-like growth looked like particularly like another SCC tumor. With all cards stacked against Mariclare’s sight, Dr. Irby’s team came up with a plan to remove her left eye after using a mask to adapt her to loss of vision on that side. Meanwhile, they would save her right eye right away through surgery and strontium-90 radiation therapy, using a radioactive probe to apply large doses of radiation.

“Radiation requires general anesthesia, a risky procedure in very large animals like Mariclare,” said Dr. Irby. “We tried to choreograph everything to minimize the time she’d be under.”

After careful anesthesia, a thorough exam revealed another tumor in her right eye. They conducted a CT (computed tomography) scan to confirm that no tumors were invading the bone or the lymph nodes in her head. Next they performed specialized surgeries to remove the right eye’s tumors. Biopsies confirmed all the tumors were SCC.

But radiation had to wait until the surgery on the left eye because Mariclare’s blood pressure began dropping. Woken to be safe, she went home to recover. There Wagner helped her acclimate to being blind on the left side with the impending loss of that eye by maintaining in place an eye mask Dr. Irby prescribed. She soon returned to Cornell, where the team successfully removed her left eye and radiated the right.

Rechecking Mariclare’s eye every six months, Dr. Irby found, removed, and irradiated a new small mass in 2010. Today, five and one half years later, Mariclare is cancer-free, able to see, and more at peace with people.

“I think the world of Dr. Irby,” said Wagner. “She did what was right, what she felt Mariclare needed, and it worked. Since meeting her Mariclare has changed. She approaches me in the field. When we pull a truck up to bring her to bring her for a checkup she gets right on. It’s a total turnaround.”

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