Boston Terrier Treated for Pituitary Macroadenoma with Radiation Therapy at Foster Hospital

When Ernie, a ten-year-old Boston Terrier, started to take on a calmer demeanor and lose his rambunctiousness, his owner, Dr. Debra Caporizzo, knew something was off.

“Ernie has a little Napoleon complex around other dogs and gets overly excited around people. He suddenly seemed more relaxed, like a normal dog. My chief complaint was that he was too well-behaved,” says Dr. Caporizzo.

A relief veterinarian and previously an ER vet, Dr. Caporizzo has had Ernie since he was eight months old. He was given to her by a friend of a friend who had difficulty training him.

At the beginning of last summer, Dr. Caporizzo noticed that Ernie no longer wanted to take long walks, which he always enjoyed. She ran bloodwork, which showed a slightly elevated alkaline phosphatase, which is not uncommon in older dogs, she explains, but not seen before with Ernie. She tested him periodically over the next few months and found the numbers continued to elevate. Other symptoms appeared, too—polyuria (increased urination), hair loss, skin infections, a pot belly, and increased hunger.

Dr. Caporizzo brought Ernie to Agape Animal Hospital in Whitinsville, Massachusetts, where she works, for an abdominal ultrasound that revealed enlarged adrenal glands. The results of the ultrasound and his symptoms were suggestive of Cushing’s disease (hyperadrenocorticism), a disease in which there is an overproduction of steroids caused by either a pituitary tumor or, less commonly, an adrenal gland tumor. Further testing confirmed the diagnosis. Subsequently, Ernie began treatment with trilostane, a drug that reduces the synthesis of steroids.

While his physical symptoms improved on medication, Dr. Caporizzo says Ernie became increasingly “mentally dull.” He also became lethargic and stopped jumping and barking at other dogs.

She scheduled an MRI at Massachusetts Veterinary Referral Hospital, where he was diagnosed with a macroadenoma, a noncancerous tumor in the pituitary gland. She was referred to Henry and Lois Foster Hospital for Small Animals (FHSA) at Cummings School of Veterinary Medicine at Tufts University.

The Oncology Team conducted another MRI to view the tumor in a one-millimeter slice to plan for radiation therapy. He started treatment at the end of May.

“The Oncology Team at Foster was excellent,” says Dr. Caporizzo. “They got me in quickly for the consult and started radiation the next week.”

Pituitary macroadenomas cause the adrenal glands to release hormones that can result in various symptoms related to Cushing’s disease, such as the symptoms that Ernie experienced in the past, as well as lethargy from a space-occupying mass in the brain (pituitary tumor), explains Dr. Celina Morimoto, assistant clinical professor of radiation oncology in the Department of Clinical Sciences at Cummings School. Radiation therapy was the best option to shrink the tumor, as chemotherapy would be ineffective against a pituitary tumor, and surgery too risky on such a complex area to access in the head. Radiation therapy could potentially alleviate the symptoms of Cushing’s disease, too.

“It’s not a common tumor, but they tend to be referred for radiation therapy,” says Dr. Morimoto. “The survival after radiation can be around three to four years with the protocol we used for Ernie. It’s a benign tumor that doesn’t spread, but it behaves in a bad way because it can cause brain symptoms.”

Over the next four weeks, Ernie received 18 radiation treatments, coming into FHSA five days a week and going under general anesthesia each time. Before every treatment, Dr. Morimoto and the Oncology Team performed daily physical exams. “Radiation therapy is a type of treatment that involves a very specialized team. We could not do it without our team here.”

“The doctors and technicians communicated with me daily all the way through,” says Dr. Caporizzo. “The technicians were great with Ernie. I had an excellent experience, and so did Ernie. They took very good care of him. He loved going there. He’d go in and get all excited to see them.”

Ernie tolerated radiation therapy well. He had a few temporary side effects that resolved with treatment, including brain swelling that improved with medications. “He always woke up quickly and eager to eat treats,” says Dr. Morimoto.

While the tumor will take three to four months to show any shrinkage, the Oncology Team observed changes in Ernie’s behavior early on in his treatment.

“We could see Ernie looking more alert, even with daily anesthesia,” says Dr. Morimoto. “He started barking at other dogs and became more active after he started radiation treatments, which his owner hadn’t seen in a long time—he fell asleep during the initial consultation. Back to normal behavior is a good sign, especially only mid-way through treatment.”

Dr. Caporizzo reports that Ernie is back to his old self and has a good quality of life, although he has yet to show interest in long walks. She will continue to treat Ernie’s Cushing’s disease with trilostane and monitor his bloodwork. They will return to FHSA in a few months to see if the tumor has shrunk.

“Ernie tolerated 18 times under anesthesia and radiation, undergoing treatment five days a week for a month. It’s remarkable that Ernie and many dogs can tolerate that. It’s not easy, but we have very dedicated pet parents, so this routine becomes manageable. This is the nature of what we do daily,” says Dr. Morimoto. “The goal is to maximize his outcome. Hopefully, he’ll get to live a long and happy life.”