By TB Thompson DVM
A cancer diagnosis can feel devastating for a dog’s human companions. But some exciting developments may make canine cancer a little less scary.
This article looks into the growing area of dog cancer immunotherapy. We’ll explore how they work, plus discuss the risks and benefits of these new treatments.
Immunotherapy Developments
Immunotherapy has been used to treat cancer in people and pets for decades. Recent advances have made it more effective and more widely available for use in dogs. 
How They’re Being Used
Immunotherapy and cancer vaccines can play a role in treating even the most difficult cases by
- Halting Tumor Progression: Cancer vaccines are designed to stop the growth and spread of tumors in a dog’s body.
- Eliminating Residual Cancer Cells: Even after surgery or radiation therapy there may be a few cancer cells in a dog’s body. Therapeutic cancer vaccines help the immune system to find and destroy these residual cells.
- Preventing Cancer Recurrence: It’s not uncommon for cancer to come back after traditional treatment. Immunotherapy trains the body to recognize and destroy cancer cells quickly, preventing any significant regrowth.
Differences Compared to Traditional Treatments
Traditional treatments like chemotherapy, radiation, and surgery attack cancer cells directly. These therapies can cause significant side effects. And they’re not always effective against aggressive cancers like hemangiosarcoma, mast cell, and oral tumors.
Immunotherapy offers a different approach by enhancing the body’s natural defenses to combat cancer. This approach often causes fewer side effects and is more effective in certain cases.
Challenges with These Treatments
Immunotherapy for dogs has its challenges. One problem is that cancer cells act differently in each dog. Immunotherapy that works well for one dog may not help at all for another one.
Cancer vaccines tend to work best on smaller amounts of cancer cells. If a large tumor can’t be removed or shrunk with radiation, immunotherapy might not be very effective.
Studying new treatments can be challenging and costly. There is more funding and interest in developing cancer immunotherapy for humans but human medicine doesn’t always work well for dogs.
What to Consider Before Pursuing Immunotherapy
Before pursuing immunotherapy, consider the availability of the therapy, the type and stage of cancer, and the health status of the dog. Remember, side effects can still occur, even though they’re often less severe than those caused by traditional treatments.
A veterinary oncologist can help you weigh the potential benefits against the risks of treatment. The table below reviews some of the pros and cons of this treatment method.
| Pros | Cons |
| Uses the dog’s natural defense mechanisms | The effectiveness can vary, depending on the individual dog’s cancer cells |
| Targeted treatments attack cancer cells, sparing healthy ones | May not be as effective for large tumors |
| May be used alongside other treatments to enhance effectiveness | More research is needed to support the widespread use of cancer immunotherapy in dogs |
| Good for treating residual cancers left behind by traditional treatment | Not all types of immunotherapeutics are readily available to the public |
Conditions These Vaccines Can Treat
Researchers are studying immunotherapeutics to treat many kinds of canine cancer. Several products are available and approved for use in dogs:
- Mast Cell Tumors: Mast cell tumors are the most common type of skin cancer in dogs. They can be difficult to remove, especially when they grow on a dog’s legs. Untreated MCTs can spread to other parts of the body. Stelfonata® is an immunotherapeutic that is injected directly into the tumor. It activates a protein that spreads through the tumor and destroys the abnormal cells. (1)
- Oral Tumors: Mouth tumors in dogs are common, aggressive and difficult to treat. Melanoma is the most common type of mouth cancer in dogs. The vaccine Oncept® trains a dog’s immune system to destroy an enzyme present in melanoma cells. One study showed these vaccines helped dogs with melanoma live longer compared to dogs that only received local therapy (2)
- Hemangiosarcomas: Hemangiosarcoma (HSA) is an aggressive, common type of cancer that arises from cells that line blood vessels. Torigen® is an autologous vaccine made from a dog’s own cancer cells. Once vaccinated, a dog’s immune system starts to recognize and destroy cancer cells. (3)
How Immunotherapy Works
A dog’s immune system normally detects and destroys abnormal cells before they become a problem. But cancer cells can escape notice by several means, including suppressing the immune response.
Cancer vaccines operate much like the vaccines we use to prevent infections like parvovirus. Only, instead of teaching the immune system to attack a foreign invader, cancer vaccines target the dog’s own abnormal cells.
By introducing cancer-specific molecules to a dog’s immune system, it becomes primed to identify and obliterate cancer cells. This means the treatment is very precise and only attacks the harmful cells, leaving the healthy ones alone.
Outlook for These Types of Cancer Vaccines
The future of anti-cancer vaccines looks hopeful. New and innovative treatments are being developed and should be available soon.
Are They Readily Available to the Public?
Some cancer vaccines are now available through veterinary oncologists and internists. However, many are still in the testing stages. Developing these therapies is a complicated process. So, it might be a while before they are widely available.
What the Future Holds for the Advancement of These Therapies
Ongoing research is helping us understand canine immunology better. We can look forward to more advanced and user-friendly immunotherapies. These new treatments could offer more options and help improve the quality of life for dogs with cancer.
Conclusion
Promising developments in canine cancer vaccines are unfolding. Researchers are finding ways to make vaccines work better and exploring how they can be used with chemotherapy.
Finally, the Vaccination Against Canine Cancer Study is studying a vaccine meant to prevent dogs from getting cancer. (4) These innovations mark substantial progress in extending the health and longevity of dogs.
References
- FDA approves first intratumoral injection to treat nonmetastatic mast cell tumors in dogs. (n.d.).https://www.aaha.org/publications/newstat/articles/2020-11/fda-approves-first-intratumoral-injection-to-treat-nonmetastatic-mast-cell-tumors-in-dogs/
- Treggiari, E., Grant, J. P., & North, S. M. (2016). A retrospective review of outcome and survival following surgery and adjuvant xenogeneic DNA vaccination in 32 dogs with oral malignant melanoma. Journal of Veterinary Medical Science, 78(5), 845-850.
- Lucroy, M. D., Clauson, R. M., Suckow, M. A., El-Tayyeb, F., & Kalinauskas, A. (2020). Evaluation of an autologous cancer vaccine for the treatment of metastatic canine hemangiosarcoma: a preliminary study. BMC veterinary research, 16(1), 447.
- Katsnelson A. (2021). Preventive Cancer Vaccine Based on Neoantigens Gets Put to the Test. ACS central science, 7(8), 1288–1291.
About the Author
TB Thompson DVM
Veterinarian
TB Thompson DVM is a licensed veterinarian who completed her studies at the University of Tennessee College of Veterinary Medicine in 2000. Leveraging her broad experience from general practice to emergency care, animal shelters, and home visits, she established Your Vet Friend to help people provide better care for their dogs and cats.
