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OCULAR ONCOLOGY
Ocular oncology is the management of
tumours in and around the eye, including
the eyelids, orbit and lacrimal glands.
Ocular tumours can occur in adults and
children, and may affect one or both
eyes.
Choroidal melanoma,
choroidal haemangioma, retinoblastoma,
eyelid tumour, conjunctival tumour and
lymphoma/leukaemia are some of the
common ocular cancers seen by
ophthalmologists.
CHOROIDAL MELANOMA
Choroidal melanoma is a tumour occurring
inside the eye, and is the most common
primary intraocular tumour in adults.
Choroidal melanoma is a
malignant tumour that can metastasize
and spread to other parts of the body
(mostly the liver). Patients with this
disease are often around the age of 60
years. They do not recognize its
presence until the tumour grows to a
size that cause decreased vision, visual
field loss, floaters, or photopsia (a
ball of light travelling across the
visual field 2-3 times a day). Regular
eye examination through a dilated pupil
is the best way of detecting the tumour.
The management of choroidal
melanoma is tailored to the individual
patient, taking into account; the size,
location and extent of the tumour; the
vision of that eye; the state of the
other eye; the general health and age of
the patient; and the patient’s wishes
and fears.
Small suspicious
tumours are usually watched closely for
signs of growth before any treatment is
started. Medium-sized tumours may be
treated with radiotherapy or by removal
of the eye. Large tumours are usually
treated by removal of the eye. Tests are
done to detect spreading of the tumour
to other parts of the body.
Patients with choroidal melanoma
undergoing evaluation and treatment at
the Pretoria Eye Institute have access
to the most advanced diagnostic testing
and treatment modalities in South
Africa.
CHOROIDAL HAEMANGIOMA
Choroidal haemangioma is a tumour
consisting of blood vessels. It is not a
cancer and never metastasizes. The
visual function may be affected when the
haemangioma is located in the area of
the central vision of the eye.
Most haemangioma can be safely monitored
by your eye doctor without the need of
further treatment. Photographs are used
to monitor evidence of growth, leakage
or the need of treatment. Laser
photocoagulation and external beam
radiation are treatment options to
decrease the amount of fluid leakage.
CHOROIDAL METASTASIS
Cancers from other parts of the body can
spread in and around the eye. Breast
cancer in women and lung cancer in men
are the most common primary tumours to
spread to the eye. Others include
prostate, kidneys, thyroid,
gastrointestinal tract cancers, and
blood cell tumours (leukaemia and
lymphoma). A team approach is followed
in treating these patients, including
eye specialist, medical oncologist, and
radiation oncologist.
Treatment
options include chemotherapy, radiation
therapy and more rarely enucleation.
CHOROIDAL NEVUS
A choroidal nevus is like a freckle on
the skin, but it occurs inside the eye.
A nevus can become a malignant tumour
and should be monitored regularly. Four
to six monthly examinations by an
ophthalmologist is needed to check for
pigment and size changes. No treatment
needed unless there is evidence of
change.
CONJUNCTIVAL TUMORS
The conjunctiva is the outer layer
covering the surface of the eye and
inside of the eyelids. Malignant cancers
include squamous cell carcinoma,
melanoma and lymphoma. Squamous cell
carcinomas invade the area around the
eye into the orbit and sinuses, but
rarely metastasize. They can start as a
freckle (nevus) or can arise form an
area of pigmentation. Lymphoma in the
eye can be evidence of systemic
lymphoma.
Most small
conjunctival tumours can be monitored by
photographs. Evidence of growth will
lead to a full or partial biopsy.
Melanoma and squamous cell carcinoma
should be surgically removed. Other
forms of therapy includes, cryotherapy
(Freezing therapy) and chemotherapy eye
drops.
EYELID TUMOURS
Malignant skin cancers, inflammation, or
benign cysts can all be found on the
eyelid. Basal cell carcinoma is the most
common eyelid tumour. The others include
squamous cell carcinomas and sebaceous
gland carcinomas.
Basal cell
carcinomas can mostly be removed
surgically. Untreated it grows around
the eye, into the orbit and sinuses. To
determine whether a tumour is malignant
or not a simple biopsy is done.
Treatment for malignant tumours is to
remove it completely and plastic surgery
techniques are used to repair the eyelid
defect. It can be completely cured.
Sometimes additional treatment may be
necessary after the surgery like
chemotherapy and radiation therapy.
IRIS TUMOURS
Many iris tumours are only cysts or a
nevus, but malignant melanoma can also
occur in the iris. Most pigmented iris
lesions do not increase in size.
Photographs and high frequency
ultrasound are used to monitor these
lesions. Treatment is only recommended
if there is documented growth. Surgical
removal of the lesions is the treatment
of choice. Radiation plaque therapy and
enucleation may be needed for larger
iris tumours.
LYMPHOMA/LEUKEAMIA
The eye, eyelid tissues and the tear
ducts can develop tumours of lymphatic
origin. Most lymphomas are large cell
non-Hodgkin’s lymphoma. The disease is
confined to the central nervous system
and the eye. Eye symptoms can appear two
years before they are seen elsewhere in
the body. The treatment consists of
external beam radiation, chemotherapy,
or both, to the central nervous system.
Visual functioning can be affected by
the disease as well as the treatment of
lymphoma.
ORBITAL TUMORS
The orbit is the bony structure around
the eye. Inflammations and tumours of
the orbit can occur behind the eye.
These tumours can often push the eye
forward (proptosis), causing a bulging
of the eye, or even downwards (like a
lacrimal tumour). Most common conditions
causing proptosis are thyroid eye
disease and lymphoma. Haemangioma,
lacrimal gland tumours and tumours from
the sinuses are other causes or orbital
tumours. The diagnosis is made by doing
special tests which includes; CT-scan,
MRI-scan and Ultrasounds, followed by a
biopsy of the tumour.
If
possible, the orbital tumour is removed
in total. When removed it may cause
damage to nearby structures a piece of
tumour is removed and sent away for
evaluation. External beam radiation can
be used as adjunct to surgical removal
or debulking. Extremely large tumours
may require removal of the eye and the
orbital contents.
Orbital
lymphomas are biopsied and treated with
radiation therapy, or chemotherapy if
other parts of the body are involved.
All patients undergo proper systemic
work-up and management by an oncologist.
RETINOBLASTOMA
Retinoblastoma is the most common
primary intraocular (inside the eye)
malignancy in children. It presents in
the first two years of life with a white
pupil, squinting eyes, glaucoma or a red
eye. These patients are evaluated using
ultrasound, CT-scan and MRI-scans. A
systemic and genetic work-up is done
with an oncologist.
Treatment of
small tumours consists of laser
photocoagulation, cryotherapy (Freezing
therapy) and chemotherapy. Medium sized
tumours can be treated using
brachytherapy (radiation), and primary
chemotherapy. In the treatment of large
tumours chemotherapy is used to shrink
the tumour, facilitating local treatment
options and avoiding enucleation and
external beam radiation. Enucleation
(removal of the eye) is indicated if
there is optic nerve involvement, or
extensive haemorrhage in the eye, or the
tumour is too large and do not respond
to chemotherapy shrinking. This is only
done as a life saving measure.
HOW IS EYE CANCER DIAGNOSED?
By performing a complete dilated eye
examination an ophthalmologist can
determine if you have an eye cancer. The
examination may include a medical
history, dilated eye exam, doing an
ultrasound, and obtaining photographs.
Your ophthalmologist may be able to
recognize an eye cancer by its
appearance. Biopsy is rarely needed with
eye cancers, because opening the eye may
risk spreading of tumour cells.
ULTRASOUND
Sound waves are directed towards the
tumour by a small probe placed on the
eye. Reflection patterns can confirm the
presence of a tumour in the eye.
Ultrasound can determine if there is
spread of tumour outside the eye, and
help determine the thickness of the
tumour. Pictures are printed for your
ophthalmologist to review.
PHOTOGRAPHY
Ophthalmologist uses mainly two types of photos to assist in diagnosis: fluorescein angiography and fundus photography. Fluorescein angiography uses a dye that is injected into the vein of the arm. Photographs are taken to view the circulation of the retina and the layers beneath the retina. The Fluorescein highlights any abnormality. In fundus photography photos are taken of the retina, macula, fovea, optic disc and retinal vessels.
ADDITIONAL EVALUATIONS
Depending on what your doctor sees in
the eye, he will request special
examinations, like CT-scans and
MRI-scans. CT-scans are series of X-ray
images that provide a clear picture of
the eyes, orbit, brain and sinuses. It
is a non-invasive quick examination.
MRI-scans use magnetic fields and a
computer to create pictures of the
inside of the body. Because MRI-scans
can “see” through bone it provides
clearer pictures of tumours.
WHAT ARE THE LATEST TREATMENT OPTIONS?
Your ophthalmologist will recommend
treatment tailored for your specific
needs. This will be based on your
medical history and the findings of the
eye examination. Not all eye cancers are
treated immediately. When the tumour is
small, your doctor may recommend
monitoring the growth closely. Treatment
will be started if there is any concern.
Treatment is usually recommended if
there is evidence of growth or if there
is a possibility of spreading to other
parts of the body.
CHEMOTHERAPY
Chemotherapy is the most common type of treatment for cancers in general. It is the treatment of cancer by means of drugs that has a specific toxic effect on cancer cells, and selectively destroys these cancer cells. Many drugs are available and each drug has potential side effects. Although rarely used in eyes, it is sometimes recommended for choroidal metastasis, conjunctival tumours, lymphoma and retinoblastoma.
CRYOTHERAPY
It is the use of very low temperature to
treat diseases and tumours. Cryotherapy
may be recommended for conjunctival or
eyelid tumours. Its goal is to freeze
the malignant tumours to stimulate
inflammation and scaring.
EXTERNAL BEAM RADIATION
High energy radiation from X-rays is
used to destroy cancer cells and shrink
tumours. It is administered by placing a
radiation plaque over the tumour
(internal radiation or brachytherapy).
The external beam radiation may be
recommended for choroidal metastasis,
choroidal haemangioma, lymphomas, eyelid
tumours and orbital tumours.
RADIATION PLAQUE THERAPY (BRACHYTHERAPY)
It is the most commonly used eye sparing
treatment for choroidal melanomas. A
radio-active plaque is a small disc
shaped device that contains a
radio-active source. The plaques are
custom made to the size of the tumour.
The radio-active plaque is surgically
placed over the tumour and the procedure
lasts about an hour. Most patients have
no problems with the plaque placement
surgery. The effects of radiation on the
tumour are only seen after three months.
Eventually the tumour shrinks, and even
though the tumour does not completely
disappear, the tumour is considered
inactive. Regular monitoring is still
needed.
ENUCLEATION
Enucleation is the surgical removal of the eye, leaving the eye muscles, eyelids, lashes, brow and skin. Enucleation is only recommended when there is no other way to remove the cancer completely from the eye. This means that the eye will be permanently blind because an eye cannot be transplanted. When the eye is removed, an implant is placed into the orbit. The muscles are sutured to the implant to allow some movement of the prosthesis. After a healing period a temporary prosthesis is fitted. It is a plastic shell painted to match the other eye, and inserted under the eyelid like a big contact lens. Most patients are very happy with the final prosthetic fitting, and say people cannot tell they have only one eye.
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