Eye Cancer (Squamous Cell Carcinoma)
Diary in the diagnosis and treatment of an eye cancer
This is the diary that I kept immediately before, during and post the diagnosis of a squamous cell carcinoma of the eye in Bishop of Bombay. Bishop is now: 23 year old handsome, bold, kind, 16.3 seal bay gelding. He was bred by Chris Snaith at his Stud Farm in Paarl and trained by Justin Snaith. He won some Grade A races before being retired with a tendon injury. He has passed through the hands of Gonda Beatrix and I met him seven years ago when I started riding him to help out his owner, a young mother with insufficient time. Bishop currently lives in a 5 hectare field where he is 'heckeled' by my mare and her yearling filly and cared for by myself. He is accommodated as naturally as possible, taking into consideration all the predilections of a Thoroughbred! I consider myself “retired”, hence Bishop is too, though we hack over wonderful country, pop logs and ditches and school regularly too maintain health, strength and fitness.
 9/1/09 Bishop’s eyes tearing and accumulation of dirt, but it is a very blustery day, so clean both eyes and think no more of it.
16/1/09 Notice pea sized dark lump in upper corner of right eye. Bishop’s eyes are very darkly pigmented and as he is generally a very relaxed individual, he seldom shows the whites (sclera) of his eyes, therefore difficult to see lump.
23/1/09 While grooming him, notice that the pea sized lump has become a centimeter in diameter with irregular edges and a messy bubble wrap appearance. It is the weekend so must to wait till Monday before I can contact the vet. Immediately suspect the worst due to appearance of lump.
Conjunctival tumours are malignant cancers that grow on the outer surface of the eye. Squamous cell carcinoma (SSC) is the most common tumour of the eye and lids in horses. It is locally aggressive and grows rapidly though they rarely metastasize (seed or spread to other areas of the body). However they can invade the area around the eye into the bony orbit and sinuses, and metastasize up the optic nerve and involve the brain if not removed timeously.
As these tumours are fast growing they cause pain evidenced by excessive blinking, discharge, holding the eye closed, rubbing and moving away when touched in the area. Recommendations are to keep clean with a saline solution and to wear a fly mask as discharge attract flies and insects increasing the risk of inflammation and infection.
Mon 26/2/09 Called vet practice in Great Brak River first thing and ask Bishop’s vet Anndri van Zyl, BVSc, MRCVS, for a home visit.
Anndri confirms problem. What to do? Options: Take a swab/scrape, or aspirate/biopsy. Agree to scrape, as least risky.
Mon 2/2/09 Phone Anndri for pathology results. Pathologist i.d.‘s only bacterial cells. (It is worth remembering that all test results are only as good as the individual interpreting them and the quality of the evidence in front of them). Anndri is trying to make arrangements of a visiting consultant eye specialist from Gauteng to see Bishop. She also suggests that taking him to Gauteng for radiology may be a possibility.
Visit my optician for new specs and we chat re Bishop’s condition, as still considering options given Bishop’s age, distance from equine facilities, cost of available treatments and likely outcome. We look at photos of various eye tumours and decide to talk to some ophthalmologists’ in town.
Speak to human eye surgeon; interested and would like to help but not allowed to borrow surgical equipment from hospital and not willing to use unfamiliar operating equipment.
Small conjunctival tumors can be photographed and monitored for evidence of growth prior to treatment. The most common form of treatment is surgical removal of the tumour and debridement of the area and it may be recommended that this is followed up with cryotherapy (freezing therapy), immunotherapy, irradiation, radio-frequency hyperthermia, CO2 laser ablation, or intralesional chemotherapy.
Tumours on the lid or around the eye may be injected with chemotherapeutic agents e.g. Cisplatin or 5-flurouracil, with Cisplacin beads placed in the surrounding tissue. Surgical lasers and topical use of mitomycin C have also shown good results. If the tumour is large, in, or behind the eye, then removal of the eye (enucleation) is usually the only effective treatment. A Tumour behind the eye can cause the eye to protrude from the socket. Loss of vision occurs and the eye may become cloudy, which is associated with glaucoma and cataract development. Radiation may be used but causes blindness and is usually used only to prolong the lifespan of the horse and post enucleation.
Herbal remedies such as Maritime Pine Bark, Comfrey, Thuyja, Hyperium, Golden Seal and Bach Flower remedy and Rescue remedy, but efficacy not proven e.g.
Fri 6/2/09 Visiting consultant specialist eye vet, Dr Izak Venter arrives thank goodness! Says it is a fairly small tumour, probably SSC and that it should be easily removed. Not yet impinging upon cornea and removal should not affect sight. Considerable relief!
Izak must return today to Gauteng, but arrangements to be made for a return flight to George a.s.a.p. We cannot afford to wait for his next scheduled visit in 3 months time.
Fri 13/2/09 All arrangements made and expecting Izak on Monday morning.
Fraught, anxious weekend for me and a tense atmosphere at Dapplemere Farm, a small private livery yard where Bishop is a popular and long term resident.
Sun 15/2/09 Bishop has supper but haynet is removed at 10pm. Must now fast till after operation. Water is available of course.
Mon 16/2/09 A warm dry, non windy day. Fortunate, as we do not have a contingency plan for bad weather.
7am Hack out in order that Bishop does not stress over having to watch stable-mates having breakfast!
This is important as physical state prior to anesthetic can affect outcome.
On return, groom and box him to await arrival of surgeon.
9.30 Drive to airport to collect Dr Izak.
9.40 Prompt arrival by One Time Airways.
Ring Anndri who will be the anesthetist to allow her time to get to farm so that operation can be performed promptly.
Have organized big strong man Greg and Head Groom Paul to assist during the operation. It is important that Bishop does not rise too soon after the op as he will be uncoordinated. Horses can incur life threatening injury when attempting to regain their feet post anesthesia.
Operation is to take place on lawn in front of the stables.
 10.30 Pre-med given by Anndri followed by the anesthetic. Bishop, 18yrs, 16.2hh T/b, solid and big boned, weighing about 520Kg, in otherwise excellent health, requires considerable anesthesia. The collapse to ground is a bit slow, but basically unproblematic.
Op site prepared. Izak ready to remove tumour, but Bishop still not sufficiently unconscious. Additional anesthetic is given…not enough…more anesthesia.
Op proceeds and tumour removed in minutes.
Antibiotic placed in eye. Then we wait for Bishop to wake up… The first attempt to rise catches us a little unawares. Although Greg and Paul are sitting on his neck and I have my weight on his head, he still manages to get his head and neck off the ground. We keep him on the ground for 3 further attempts to rise. After 20minutes and his 4th attempt, he manages to regain his feet but is uncoordinated and stumbles towards a parked car. He falls, narrowly avoiding damaging himself and the car. He gets up again, then stumbles and is brought down in a flying tackle by vet Anndri followed by the assistance of the rest of us. After a further 10minutes on the ground Bishop is finally on feet, but very wobbly! Me too!
11.15 Anndri departs leaving instructions for his after care; Cortisone drops to be applied 3 x day.
 Supportative treatment includes triple antibiotic ophthalmic ointments and anti-inflammatories. Some research indicates that Cyclooxygenase-2(COX-2) plays a role in inhibiting development of SCC. Equiloxx a specific COX-2 inhibitor, may be more effective, but further research needed.
Izak and I leave for the airport. Bishop stays wobbling in the sun in the care of friend and moral support extraordinaire Marilize, together with Paul.
11.45 Return to stables. Bishop still very quiet and unsteady.
12.30 Bishop starts grazing and has a small lunch of very damp sugar beet (Speedibeet) and rolled oats. Leave him quietly grazing on the lawn, wearing his fly mask and sufficiently ‘with it’ to want to join his buddies in the adjoining field.
Leave to attend to other business, but still under the watchful eye of Paul.
4pm Return to swab eye and put in drops. The eye is exuding a small amount of blood.
Tues 17/2/09 am Has peed, normal supper, breakfast etc. and drank copiously. Very good! Eye discharging lightly, but otherwise looking good and keen to kick up his heels with his buds.
Turned out wearing his fly mask. Treatment with antibiotic and cortisone drops 4 x day. Virtually no discharge but a little tearing. Continuing to wear face day and night to keep off flies attracted by the eye secretions…really don’t need an infection at this point! Also must protect eye from UV.
Wed 18/2/09 Hacked out…fresh and keen, couple of spooks. Lacking work or vision problem?
In the evening Isak’s partner calls to say that pathology report confirms SSC, but all tumour has been removed and margins (tissue bordering the tumour) are clear. He warns that in 50% of cases the cancer may re-occur.
20/2/09 Usual hacking and schooling continues. Bishop strong and keen.
23/2/09 Treatment with cortisone and antibiotic drops continue. Eye still slightly discharging and excised area a little inflamed but otherwise satisfactory.
1/3/09 Eye dry, excision site deep pink, smooth and healthy looking.
8/3/09 Granulation tissue (proud flesh) growing at a rapid rate…totaling covering excised area). Treatment with cortisone intensified.
15/3/09 Granulation tissue resolved. Area now appearing normal. Fingers and toes crossed.
Bishop will continue to wear his fly mask at all times when outside, as UV is a major factor in the cause of SSC.
SCC may be related to the ultraviolet (UV) component of solar radiation, periocular pigmentation and an increased susceptibility to carcinogenesis.
Prevalence in horses increases with age. Cold bloods such as Belgians, Clydesdales and other draft horses have a high prevalence of ocular SCC, followed by Appaloosas and Paints (skewbalds and piebalds). Horses with little pigmentation such as cremellos, greys and palominos are also predisposed to ocular SCC. The least prevalence is found in Arabians, Thoroughbreds and Quarter horses and bay, brown and black horses. The form of treatment offered and or available will largely be dependent upon Geographic’s and economics. Regions where there are large numbers of owners with large numbers of valuable equines are more likely to have specialist vets with specialist facilities and technologies. All treatments may fail to effect a cure in many horses and SCC may reoccur in up to 68% of horses. One study showed that horses were euthanized between 2 months -5years post diagnosis and treatment due to recurrence, metastasis and complications.
Izak Venter MMedVet(Optha) has a busy practice in Magaliesburg. He regularly consults on the Garden Route and travels to Kuala Lumpur, Hong Kong, Dubai and Abu Dhabi where he both consults and lectures. He writes:
“Bishop presented with a raised black lesion on the conjunctiva of the right eye. This mass was just starting to infiltrate into the cornea and about 1 mm of the cornea was involved. The most likely diagnosis for this in a horse is a Squamous cell carcinoma [SCC]. The cause may be related to the ultraviolet component of solar radiation. The prevalence rates in horses increase with age and the mean age at diagnosis is plus minus 11 years. SCC may affect the third eyelid, eyelids, conjunctiva and or cornea. Untreated ocular SCC can invade local soft tissues, the bony orbit, sinuses and brain, but is unlikely to metastasize. If they do metastasize they spread to local lymph nodes, salivary glands and thorax.
Surgical removal is the treatment of choice for conjunctival, corneal and third eyelid SCC. Other treatment modalities include cryosurgery [freezing the tumour], radiation, chemotherapy and immunotherapy. At present our treatment of choice for eyelid SCC is chemotherapy.
Eyelid tattooing is advocated by some people to prevent eyelid SCC, although it will lead to black eyelid margins it does not decrease the incidence of SCC and may lead to eyelid scarring.”
UPDATE: JANUARY 2013 BISHOP WELL!!!!
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