• Low dose rate ‘iridium wire’ technique requires
the isolation of the horse for several days whilst
the wires were in situ.
• A new technique of high dose rate brachytherapy
has been developed and is administered to horses
under standing sedation. The treatment times
are very short (average 2-8 min) and the horse
is not ‘radioactive’ between treatments, so can
be treated as normal. The reported success rate
is extremely high and this treatment is likely to
become the ‘gold standard’ for the treatment of
periorbital sarcoids in the horse.
Teletherapy
• Effective - but rarely available.
Topical treatment
• AW5-LUDES consists of a number of heavy
metal salts and two anti-mitotic compounds
(5-fluorouracil and thiouracil) in various
combinations.
• Very effective, cheap and convenient, must be
applied by a veterinarian so the cost to the client
does mount up with veterinary visits.
• Latest formulations appear to preferentially
penetrate tumor tissue and have less effect on
normal tissue.
• Rapid and complete necrosis of tumor tissue with
formation of an eschar which eventually sloughs.
• No effect on sarcoids remote from the treated
lesion.
• Not suitable for periocular lesions.
• Any previous interference, eg biopsy, cryosurgery
decreases efficacy significantly.
• May be scar contracture and deformity at some
sites commissures of mouth and eyelids.
• Not suitable for Type A nodular sarcoid unless
there is an epidermal component (Type B nodules).
• Arsenic paste or butter of antimony are dangerous
but may prove beneficial.
• 5-Fluorouracil ointment (EFUDIX, Roche,
UK) is useful for occult and verrucose lesions.
Applications have to be made frequently and
the skin does become very sore as the epidermis
sloughs. Good results can be achieved in some
sites and this is very useful where AW5 cannot be
used.
• Compounds containing up to 25% zinc chloride
(often coupled with plant extracts) are also
available (XXterra/Sarc-Off). These commercial
materials have no advantage over the pure zinc
chloride paste and are very much more expensive.
Some successes are to be expected since the
material is directly tissue toxic causing necrosis
and sloughing of all desiccated/necrotic tissue.
• Topical retinoids are being explored as adjunctive
treatments in some occult and verrucose forms
of the disease. No significant trial information is
published thus far.
• Topical treatments using antimitotics and retinoids
should be avoided during pregnancy.
Surgery
• Case selection is critical to achieving good results.
• Significant threats of recurrence both from
incomplete removal or from seeding of the wound
bed with cells released from the tumor during
surgery.
• Special precautions are essential - failure rates of
up to 90% have been reported with sharp surgical
excision.
• Problem with regrowth and occasionally satellite
lesions.
• Useful for nodular sarcoids with no dermal
component.
• Laser surgery (and diathermy) carries a better
• Volume 21 Issue 3 | September 2019 •
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