[Successful treatment of an equine sarcoid. Case report on a combined surgical and photodynamic therapy].

The research examines the success of combining surgical and photodynamic treatment in a horse with a skin tumor known as an equine sarcoid. It highlights the use of a specific drug and red-light laser for treatment and results in the total dismissal or halt in growth of the tumors.

Combining Surgical and Photodynamic Therapy

• The study presents the case of a 6-year-old male horse (gelding) that was diagnosed with an equine sarcoid, a common skin tumor in horses. The gelding had a mass on the ventral prepuce (part of the penis), several tumors on the lateral aspect of the prepuce, and another sarcoid on the chest.
• In this instance, treatment involved a combination of both surgical removal and what is known as photodynamic therapy (PDT). PDT is a treatment that uses a drug, known as a photosensitizer (in this case, Temoporfin, also known as Fospeg®), which is activated by a specific wavelength of light. When this photosensitizer is exposed to this light in the presence of oxygen, a form of oxygen that can kill cells forms.

Procedure

• Temoporfin was injected locally at a concentration of 0.15mg/mL into the areas of the gelding affected by the tumors. The use of Temoporfin (Fospeg®), produced by Biolitec AG, is specifically highlighted. This medication is photosensitive and reacts when exposed to a specific light wavelength. This reaction leads to the destruction of the targeted cells.
• Following the injections, the treated areas were exposed to a red-light laser at a wavelength of 652nm and an energy density of 10J/cm². This exposure triggers the drug’s properties, leading to a reaction that results in the destruction of the tumors.

Results

• The mass on the ventral aspect of the prepuce and some of the lateral tumors underwent total remission, meaning they disappeared entirely. Meanwhile, the remaining tumors either decreased in size or stopped growing. This shows the potential effectiveness of the combined surgical and photodynamic approach in treating equine sarcoids.
• The research suggests that there could be significant potential for the use of this combined method as part of a treatment strategy for equine sarcoids and potentially other types of tumors as well.