Researchers looked at a method to treat equine sarcoids (the most common type of skin tumor in the horse) using autologous vaccination. This is a method whereby the treatment itself is produced by isolating tumor cells from an individual and processing these tumor cells into a vaccine formulation that is then administered to the individual from whom the tumor cells were isolated. Sarcoids are not true cancer in that they do not metastasize, and it is believed that bovine papillomavirus and some genetic component of the horse itself can cause them. In this study, 18 horses with sarcoids had the procedure performed. The sarcoid lesion was debulked (surgical removal of a part of the tumor), and the removed portion was sectioned into very small cubes. These pieces were then placed into liquid nitrogen to kill the virus.
These pieces were then implanted back into the horse’s neck just below the nuchal ligament. Their results were very encouraging on those horses available for long-term follow-up, with 12/16 (75%) showing a decrease in the number of sarcoids with 15/16 (93.8%) showing a decrease in the size of their tumors. Complete regression was seen in 11/16 (88%) of cases.
The authors concluded, “although the mechanism of the autologous preparation is unknown, we suspect the tissue acts as an immunomodulatory agent to stimulate a host response not only against the debulked lesion but on other lesions on the body.”
Scientific Article: Rothacker, CC, Boyle, AG, and Levine, DG. Autologous Vaccination for the Treatment of Equine Sarcoids: 18 cases (2009-2014). AAEP Proc. vol. 61, 2015, p. 154.