Two years after their program began, Dr. Craig Webb, professor of Small Animal Internal Medicine at the James L. Voss Veterinary Teaching Hospital, and the team from the Feline Cancer Core are excited about their growing understanding of gastrointestinal (GI) lymphoma in cats.
“We’re approaching our 100th study entrant, which is actually pretty amazing,” said Webb.
When they started their project, the team outlined four critical questions:
- What is the best way to confidently distinguish between feline Inflammatory Bowel Disease (IBD) and feline GI lymphoma?
- What genetic and environmental factors contribute to the development of IBD and lymphoma?
- Does chronic feline IBD progress or transform into feline GI lymphoma over time?
- What therapies can be developed to treat IBD and GI lymphoma?
In a relatively short time, they’ve uncovered some interesting answers.
Is it feline IBD or GI lymphoma?
Discerning the difference between IBD and GI lymphoma study starts with an endoscopy performed on feline patients presenting with symptoms of the two diseases. During the procedure, Webb and residents in the Small Animal Internal Medicine service collect samples from the patients sent to the lab for study.
“As we perform the various tissue tests, it is becoming more and more clear that relying on histopathology alone – previously considered the gold standard – is simply not likely to give you the most complete and accurate answer,” said Webb.
The bulk of the laboratory research is done by Dr. Paula Schaffer, who examines the tissue samples, and Dr. Anne Avery’s Hematopathology Laboratory, where they are performing molecular testing. Through this testing, including Immunohistochemistry (IHC), and in particular, polymerase chain reaction (PCR) for antigen receptor rearrangement (PARR), CSU scientists have discovered that different areas of the GI tract can have distinctly different disease processes (inflammatory, fibrotic, neoplastic), and can even have different forms of T cell lymphoma . This discovery has significant implications for both treatment choices and prognosis.
“This finding is critical because the actual diagnosis will be missed if made on histopathology alone, and that would keep the patient from getting the most appropriate treatment,” said Webb.
What factors contribute to feline IBD and GI lymphoma?
To begin understanding the genetic and environmental factors that lead to feline IBD and lymphoma, in July 2021, the Feline Cancer Core is launching a nationwide survey for cat owners. According to Webb, this will be a significant step in collecting the data necessary to identify contributing factors. The project is similar to other veterinary studies, including the Golden Retriever Lifetime Study, which compiles nutritional, environmental, lifestyle, and medical data from 3,000 Golden Retrievers.
Does feline IBD become feline GI lymphoma over time?
The answer to this question will take time. Webb and the team are looking at designing a project to follow patients diagnosed with IBD for several years. The study will require a partnership with owners who commit to ongoing follow-up and multiple biopsies of their cats over time. Webb believes this type of project is necessary to help the team better understand the relationship between the two diseases.
What therapies can be developed to treat IBD and GI lymphoma?
Dr. Jenna Burton, a medical oncologist at the Flint Animal Cancer Center, is working on a critical study of the pharmacokinetics (absorption, distribution, metabolism, and excretion) of chlorambucil, a chemotherapy used in cats with GI lymphoma.
“The goal of treatment is to decrease and ideally resolve the symptoms of GI lymphoma, such as vomiting, diarrhea, and weight loss,” said Burton. “Frustratingly, sometimes the chlorambucil itself can cause those same signs, and it can be challenging for veterinarians to sort out whether it is the treatment or the disease that is the issue. The purpose of our study is to understand how the drug is metabolized in cats and look for clues as to why some cats may experience side effects of the medication while most do not. The goal is to find better treatment for cats with this cancer.”
According to Webb, the next step in clinical research is likely to follow Dr. Burton’s chlorambucil study. The hope is to use the information gathered from the first study to try to determine the most effective way to use chlorambucil with prednisolone, without prednisolone, how much, and how often.
“It’s very exciting to be moving forward with studies trying to determine the optimal treatment for what is clearly a very prevalent disease of our cats,” said Webb.
On the laboratory side, Avery looks forward to further examining the complexities of the T cell populations in the feline GI tract, and “Thanks to Craig’s successful enrollment, we are inundated with samples to study,” said Avery.
“With additional resources, we look forward to digging in and continuing to learn all we can.”
Overall, the team is excited about what they’ve learned to date and what’s to come.
“What is stunning is that almost every cat seems to tell us something new about this cancer,” said Webb
This research was supported by generous gifts to our feline research programs. To support future work, please consider a gift to Angelo Feline Therapeutic fund.