New Patients Welcome: OVC Researchers Evaluating Non-Surgical Treatment for Cats with Oral Cancer

Researchers at the Ontario Veterinary College (OVC) are seeking feline patients to participate in a study exploring a minimally invasive treatment for oral cancer. Led by Dr. Michelle Oblak, Animal Health Partners Research Chair in Veterinary Medical Innovation, the research team is evaluating the use of nanoparticles and laser light therapy as a non-surgical treatment approach for cats diagnosed with oral cavity squamous cell carcinoma (OCSCC). 

About OCSCC 

OCSCC is a relatively common and aggressive type of oral cancer in cats. It typically originates in the tissues of the mouth, including the gums, tongue and palate and presents as an ulcerative lesion that can cause drooling, bad breath and difficulty eating. 

OCSCC often progresses rapidly, invading surrounding tissues and bone within the oral cavity. Although rare, the disease may also spread to lymph nodes and organs. While the exact cause is not fully understood, factors such as chronic inflammation, exposure to carcinogens and viral infections (such as papillomavirus) may contribute to its development. 

Poor Treatment Prognosis 

Early detection is an important factor in optimizing treatment outcomes for cats with OCSCC. Treatment approaches vary depending on the tumour size and location, and whether or not the cancer has spread. 

Sadly, even with treatment, the prognosis for most cats is poor: cats treated with surgery, chemotherapy or radiation typically live for only one to four months. Less than 10 per cent of cats survive for one year after diagnosis. 

In most cases, treatment is aimed at managing the primary tumour and potential metastasis, as well as providing pain management. 

A New Treatment Approach 

Dr. Michelle Oblak is a veterinary surgical oncologist and professor in OVC’s Department of Clinical Studies. She is a recognized leader in translational research that explores novel approaches to cancer staging and treatment, including lymph node mapping, image-guided therapeutics and the use of 3D printing for surgical planning and reconstruction. 

In this study, Oblak’s team combines light-activated nanoparticles (called Porphysomes) and photodynamic therapy (PDT) to target and destroy tumours. 

“We start by injecting Porphysomes into the patient’s bloodstream,” explains Oblak. “These nanoparticles preferentially accumulate in cancerous tissues. Using a specialized camera and light system, we can make them glow in the dark to quickly visualize the tumour, its margins and where the cancer has spread.” 

An added benefit of Porphysomes is that they make tissue more vulnerable to damage from laser light. The team uses an optical fiber to deliver a precise beam of laser light to the affected tissue, which activates the Porphysomes and induces tumour cell death without harming healthy surrounding tissues. This treatment may also potentially help in controlling the spread of the tumour. 

Oblak says the combination of Porphysomes and PDT is a welcome alternative to surgery. 

“We know that surgery may not be the best option for cats with OCSCC. And adjuvant therapies like chemotherapy and radiation generally do nothing to improve the overall survival rate of OCSCC. This treatment gives us a less-invasive option that shortens recovery time and reduces side effects, scarring and nerve damage associated with surgery.” 

PDT has been used previously at OVC in dogs with thyroid cancer, and Oblak’s team is currently testing the therapy in dogs with all types of oral tumours. 

Collaborative Research that Benefits Pets and People 

Oblak’s research is helping to refine the use of Porphysomes in naturally occurring cancers in companion animals. Her Porphysome studies are conducted in collaboration with researchers and human surgeons at the Princess Margaret Cancer Centre and the University Health Network (UHN), including Dr. Gang Zheng, the inventor of this technology. Teams at both the Princess Margaret and UHN are exploring the use of PDT for treating various types of human cancer. 

“The working partnership we’ve established between scientists, veterinarians and human clinicians benefits us all equally,” says Charly McKenna, research manager for OVC Clinical Trials and the Veterinary Medical Innovation program.  

UHN head and neck surgeon, Dr. Jonathan Irish, shares that this oral tumour clinical trial in cats, which is funded by the Canadian Cancer Society, will inform the human clinical trials funded by the Ontario Institute for Cancer Research and the Terry Fox Research Institute. He adds that phase 1 human studies are expected to begin later this year. 

“This study is a perfect example of a Bench to Bedside approach, where our OVC companion animal patients bridge the gap between laboratory studies and the use of this technology in humans,” says McKenna. “The same vials of nanoparticles that we’re using in cats at OVC will be used in humans at UHN, with the same potential to improve cancer treatment. This work is very exciting and holds a great deal of promise for pets and people alike.” 

How to Enroll 

Oblak’s study is currently open and welcoming cats with a confirmed diagnosis of OCSCC. If you have or know of a cat who may be a suitable candidate for this study, please email ovc.clinicaltrials@uoguelph.ca.