There are around 40 different treatments used worldwide. This suggests that no single method is universally effective. The treatments available have variable effects; some can be very successful on some occasions and ineffective on others. Lesions that look the same and are in the same anatomical region may respond differently to the same treatment type!
Failure of treatment is usually followed by the reappearance of a more aggressive tumour, and often in increased numbers. It is important to select the best possible treatment as the first option. Repeated failures bias the long term outcome to failure. Horses should be treated at an early stage in the disease when lesions are small. Effective treatment is more certain if lesions are treated early, and if the horse is under 4-6 years of age. A very neglected lesion will require an extensive and aggressive treatment protocol which may have a big impact on the horse.
There are various treatments available:
- Radiation : This gives by far the best results but is very expensive and restricted – there are only two or three centres worldwide where this treatment can be done. It is reserved for difficult lesions such as around the eye or over joints, and where owners can afford to invest the considerable sums involved.
- In the UK the only centre doing this is the Animal Health Trust in Newmarket
- Topical therapy: AW5, Bleomycin, Efudix (5-Fluoro-uracil cream), Aldara (Imiquimod), Exterra/Blood Root Ointment, Retinoid drugs (Zorac), Aciclovir.
- Surgical removal
- Intralesional chemotherapy
- Cryosurgery (freezing)
- Photodynamic therapy
- Immune methods: BCG injection