An aggressive type of brain tumor called a “glioma” took the life of Sen. Edward “Ted” Kennedy in 2009. Although Kennedy's struggle shined the national spotlight on malignant gliomas for the first time, these tumors were already the second leading cause of cancer deaths for men younger than 40 and women younger than 20.
“Despite years of research on new treatment approaches, the survival statistic hasn’t changed,” said Dr. John Rossmeisl, a neurologist in the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech. “If you are diagnosed with a glioma, you typically have just over a year to live.”
Rossmeisl, an associate professor of neurology and neurosurgery in the Department of Small Animal Clinical Sciences, turned his attention to dogs to develop new therapeutic techniques to treat high-grade gliomas and other forms of brain cancer.
“We are developing technology that destroys these types of brain tumors and opens up the blood-brain barrier so that we can get life-saving drugs to the brain in both dogs and humans,” said Rossmeisl, who received the 2014 Zoetis Award for Research Excellence, the veterinary college’s top research accolade.
This type of tumor arises from glial cells — cells that provide a number of supporting roles in the brain — and accounts for the majority of malignant brain cancers. According to statistics from the American Cancer Society, more than 14,000 people will die from brain and spinal cord tumors in 2014. Glioblastomas, a common and aggressive type of gliomas that look like “spilled milk” on a brain scan, have the lowest five-year survival rate among all types of brain tumors.
The tumors are three times more common in dogs than people, but both exhibit similar clinical signs. Rossmeisl and his colleagues are overseeing clinical trials for spontaneous cases of these gliomas in dogs.
“Because dogs, especially certain breeds of dogs, develop gliomas spontaneously, our work is much more representative of what you would find in nature than it would be in a traditional laboratory setting,” he said.
His research is an example of translational medicine, which focuses on turning biological discoveries into clinical solutions for patients, whether humans or animals. It also is part of the growing One Health initiative that is united human and animal medicine. The One Health approach is dedicated to improving the lives of all species through the integration of human medicine, veterinary medicine, and environmental science.
Rossmeisl established partnerships with Virginia Tech’s College of Engineering and Wake Forest University’s School of Biomedical Engineering and Sciences to develop new and improved therapeutic approaches. He and his colleagues have identified two novel receptors that are present in cancer cells but absent in normal brain cells.
“These receptors offer unique targets for delivery of toxins to the brain that will kill the cancer cells without harming the rest of the brain. We have already demonstrated that a drug using these receptors will work in both dogs and humans,” Rossmeisl said. “We went into this looking for a receptor that would work for this specific form of cancer, but now we’ve found that it is a marker for other types of brain tumors as well.”
Rossmeisl and Rafael Davalos, associate professor of biomedical engineering in the College of Engineering, recently completed a clinical train on irreversible electroporation, or the use of electrical fields to deliver cancer-fighting medication past the blood-brain barrier.
“Based on the results of the study, we found that the technique is sufficiently safe to justify being used for people as well as dogs,” Rossmeisl said. “A mini-schnauzer in the clinical trial is still going strong three years after treatment for a glioma.”
He is overseeing another clinical trial on the use of convection-enhanced delivery, a type of targeted chemotherapy. This treatment involves inserting a specially designed catheter directly into the tumor and infusing it with drugs over several hours. Chris Rylander, assistant professor of biomedical engineering with the Institute of Critical Technology and Applied Science, invented a unique catheter for the study.
Each of these clinical trials involves about 16 dogs receiving treatment at the college’s Veterinary Teaching Hospital over two or three years. Although most small animal hospitals might not have the technology or training to offer these treatments for their patients, Rossmeisl said that he hopes veterinary specialists will incorporate these treatments into their practice and that other veterinarians will eventually offer a cancer-fighting drug tested in one of these trials.
When Ken Johnson heard about the brain cancer research done by Dr. John Rossmeisl, a neurologist in the Virginia-Maryland Regional College of Veterinary Medicine, he said he wanted to help. Johnson created the nonprofit Boo Radley Foundation in honor of his Labrador retriever, Boo Radley, who had a glioblastoma, an aggressive type of glioma.
The foundation helps pet owners whose dogs are showing signs of brain cancer to enroll in clinical trials. These trials often involve significant entry-level costs, including travel costs to animal hospitals such as the college’s Veterinary Teaching Hospital.
The veterinary college has partnered with The Boo Radley Foundation to alleviate these costs. According to Rossmeisl, the foundation has assisted the majority of client-owned animals in his recent clinical trials.
Dr. John Rossmeisl, a neurologist in the Virginia-Maryland Regional College of Veterinary Medicine, is testing improved ways to deliver radiation therapy to dogs with other forms of brain cancer. Although the veterinary standard calls for fractional radiotherapy delivered with a linear accelerator, Rossmeisl is working to perfect the use of stereotactic radiosurgery, also known as the “gamma knife.”
Gamma knife technology delivers a beam of cancer-killing radiation with pinpoint accuracy and only takes one session over a few hours, as opposed to multiple sessions over several weeks.
The Veterinary Teaching Hospital is the only animal hospital in the U.S. offering this treatment option. Veterinarians at the teaching hospital in Blacksburg, Va., take patients to Winston-Salem, N.C., where Wake Forest University has the gamma knife equipment.
When Yeller got brain cancer, his family turned to Dr. John Rossmeisl and his colleagues at the Virginia-Maryland Regional College of Veterinary Medicine for help.