Last Updated on March 24, 2022 by Allison Price
There are many treatment options available for melanomas found in the guttural pouch or neck of your horse. Horse owners still have a lot of problems with metastatic melanoma.
You know that melanomas are best treated when they are still in their remission state. It can be challenging to manage large tumors that have spread to distant locations or become metastatic (locally invasive)
If the masses within the guttural pouch cause problems by growing into blood vessels, or impinging one or more of multiple cranial nerves running through the pouches they should be left alone.
I recommend that you have the masses of the neck evaluated to determine if they are suitable for laser surgery. Or intralesional chemotherapy. This involves injecting drugs such as cisplatin directly into them. A tissue-based vaccine is also an option. This involves sending a sample from your horse’s melanoma to a company to create a vaccine you can give to your horse.
While it might not seem like cimetidine is causing a decrease in mass size, it could be slowing their growth. This could be beneficial for the masses of the guttural pouch.
The future holds promise in gene therapy for melanomas management.
Oncept(tm), a vaccine for dogs suffering from melanoma in the oral cavity, is one example. This form of melanoma is different from the melanoma in horses. The canine oral form of melanoma causes the dog to die within months. That melanoma in horses is more benign and causes mainly local problems.
Common examples include melanomas that form at the base or end of the tail and obstruct the anal area. While most vaccines are intended to prevent disease, the melanoma vaccination is used to treat dogs with melanoma.
It is a vaccine because it induces an immune reaction when it is administered.
The vaccine is encoded by a gene for human tyrosinase. Exposure to the foreign protein causes the immune cells of the dog to recognize the tyrosinase found in tumor cells and destroy them. Although it has not been evaluated in horses with melanomas, it will.
A second new treatment recently reported also uses gene therapy and involves injecting DNA segments that code for human interleukins–molecules that promote an inflammatory response–directly into equine melanomas.
The tumors experienced significant regression in 12 of the 12 injections, and disappeared completely in one instance. The mapping and definition of gene sequences within the horse genome has enabled a better understanding of many diseases, which allows for highly targeted research into ways to combat them.
One such disease is melanoma in horses. Gene therapy may be an option for owners and veterinarians to provide effective treatment.
Kim A. Sprayberry D.V.M. answered this question. She is a board-certified intern medicine specialist who frequently works with racehorses as well as other horses suffering from respiratory tract disease. Sprayberry graduated from veterinary school at the University of California-Davis in 1988. She then worked at Southern California’s racetracks before returning home to Cal-Davis in 1994 for an internship in internal medicine. Sprayberry practices full-time, but she is also very active in veterinary medical journalism. She has been an assistant editor for Journal of the American Veterinary Medical Association as well as American Journal of Veterinary Research. Sprayberry is currently a coeditor of the textbook series Current Therapy in Equine Medicine. She also contributes to many other veterinary publications. Sprayberry was a member the Necropsy Committee, headed by Mary Scollay D.V.M. Sprayberry assisted in the development of Kentucky’s mandatory necropsy plan. She is also a director of the Equine Health and Welfare Association and Equinext, a biotech company.
