What is eye cancer?
Eye cancer is an uncontrolled growth of abnormal cells in or around the eye that develops into a tumour. Eye cancer is classified into primary and secondary. Primary intraocular cancer develops within the eye itself. Secondary intraocular cancer or metastatic cancer develops from other parts of the body and gradually affects the eyes. Breast cancer and lung cancer are the most common types of cancer that cause secondary eye cancer.
The eye is made up of three main parts namely the eyeball, the orbit (the eye socket, muscles, and nerves that surround the eyeball), and the adnexal structures (accessory structures, such as the eyelid and tear ducts). Primary eye cancers could develop in any of these three parts.
What are the types of eye cancer?
Eye cancer usually affects the outer part of your eyes. But when cancer starts inside the eyeball, it is called primary intraocular cancer. The most common forms of primary intraocular cancer in adults is melanoma and lymphoma. The common eye cancer in children is retinoblastoma, which starts in the cells of the retina. The most common type of eye cancers is as follows:
- Ocular Melanoma – The most common cancer that starts in the eye in adults is melanoma, also known as ocular melanoma. Melanoma is cancer that starts in the cells that make the pigment that gives your skin, hair and eyes colour. Ocular melanoma is also known as uveal melanoma because it often starts in the part of the eyeball called the uvea. The uvea is a layer in the eyewall that is between the sclera and retina. Melanomas in the iris often grow slowly and do not spread to other parts of the body.
- Primary Intraocular Lymphoma – Lymphoma of the eye is a cancer that involves white blood cells (lymphocytes). Lymphomas can also start in such organs as the lungs, stomach, but rarely the eyes. Lymphoma of the eye often occurs with the primary central nervous system lymphoma (PCNSL), which is a lymphoma of the brain.
- Retinoblastoma – Retinoblastoma affects young children. A genetic mutation causes retinoblastoma. It starts in the retina. Retina nerve cells start to grow and multiply.
The other types of Eye Cancers
There are other types of eye cancers and they include:
- Ocular metastases, which spread from other organs, like the breast or lungs, to the eye. They are commonly found in the choroid, which has many blood vessels. Cancer cells flow through the bloodstream from a distant organ to the eye. It is the most common cancer found in the eye of adults.
- Orbital cancers affect the tissues surrounding the eyeball which is also called the orbit. These tissues include muscles that move the eyeball around and the nerves attached to the eyeball.
- Adnexal cancers affect the accessory structures around the eyeball which are known as adnexal structures. These could include the eyelids and tear glands.
How does eye cancer develop?
Cancer develops when a genetic mutation or mutations causes old or damaged cells to continue to divide and multiply uncontrollably. In most cases of eye cancer, the mutations are not inherited but are formed throughout a person’s lifetime. Retinoblastoma in children is an inherited or genetically linked condition in approximately 25% to 30% of cases due to a mutation in the retinoblastoma gene (RB1).
What are the symptoms of eye cancer and retinoblastoma?
People with eye cancer often have no symptoms. But when symptoms do occur, they include the following:
- Glaucoma (elevated intraocular pressure)
- Painless vision loss
- Seeing flashes of light
- Eye floaters or eye flashes
- Blurred vision
- A decrease in vision accompanied by pain
- Bulging of one eye or both (proptosis)
- Change in colour of the iris
Children with retinoblastoma may have the following symptoms:
- Eyes appear to be looking in different directions
- Eye redness and swelling of the eye
- White colour in the pupil of the eye when light is shone in the eye, such as when taking a flash photograph
- Excessive tearing
If you have a child with retinoblastoma, it increases the risk that other siblings could also develop this type of cancer. Parents and siblings of children with retinoblastoma should be screened by an ophthalmologist. Siblings should continue to be screened until adolescence. You can also choose to have a blood sample screened to examine if you have the defective gene (RB1) linked to retinoblastoma.
What are the risk factors for eye cancer?
Several factors may increase your chances of developing primary eye cancer. The common risk factors include:
- Eye Colour: People with light-coloured irises are more prone to developing uveal melanoma (cancer of the iris) than people with dark-coloured eyes.
- Age and Gender: Eye Cancer is more common in men than in women, although it can develop at any age, your risk increases with age.
- Inherited Medical Conditions: Conditions like dysplastic nevus syndrome (multiple inherited melanomas), oculodermal melanocytosis or nevus of Ota (abnormal brown spots on the uvea, a pigment layering your iris), or BAP1 cancer syndrome are known risk factors for eye cancer.
- Moles: Different types of moles (nevi) in the eye or on the skin are associated with an increased risk of uveal eye melanoma.
- Certain occupations, including welders, farmers, fishermen, chemical workers, and laundry workers
- Exposure to natural UV rays (sun rays) or artificial UV rays
- Weakened immune system
How is eye cancer diagnosed?
Early screening is the key to diagnose and treat eye cancer. During a routine eye examination, doctors can notice symptoms. Tumours cause your eyes to leak fluid or make the affected area darker than other areas. In case such symptoms are noticed, then an ultrasound is recommended to get detailed images of the area.
Another vision care test that doctors use is fluorescein angiography. The ophthalmologist will put a dye into your bloodstream through a blood vessel in your arm. When it goes into your eyes, a special camera takes images of your eyes internally. This method helps establish blockage or tiny leaks. The specialist may take a small sample of the tissue to examine it further under a microscope.
What are the stages of Eye cancer?
Cancer staging is a way of describing cancer in terms of size, location, whether it has spread, and whether it is affecting other organs.
- Stage 1: When the tumour is small (less than 3 mm), it does not involve other parts of the eye, nor has it spread to other body parts.
- Stage 2: When the tumour size is a little larger than stage 1 but has not spread to other parts of the eye or body.
- Stage 3: When the tumour size is large and has spread to other parts of the eye.
- Stage 4: When cancer has spread to other parts of the body and is said to have metastasized.
How is eye cancer treated?
The goal of eye cancer treatment is to reduce the risk of the cancer spreading, to maintain your vision as much as possible, and to prevent a recurrence of cancer.
Surgery is done to remove the tumour along with the surrounding healthy tissue during an operation. This is also called surgical resection. Eye surgery is typically performed by an ophthalmologist. Surgery to the eye is common in the treatment of intraocular melanoma. During surgery, the ophthalmologist removes parts or the entire affected eye depending on the size and spread of the tumour.
The surgical options include:
- Iridectomy: This is the removal of part of the iris
- Iridocyclectomy: This is the removal of part of the iris and ciliary body
- Sclerouvectomy/endoresection: This surgery is to remove the choroidal tumour while keeping the eye
- Enucleation: This is the removal of the entire eye
The potential side effects of eye surgery are similar to that of any surgery, which includes a risk of infection, problems from the general anaesthesia (the medication used during surgery), and pain. With total removal of the eye, there is a slight risk that the tumour may recur in the orbit.
Radiation therapy uses high energy beams from X-rays and protons that destroy cancer cells. It is delivered by external beam radiation or brachytherapy.
- Radiation therapy to treat the tumour can result in some vision loss, so doctors may recommend other treatments first.
- Radiation therapy may result in a variety of side effects, for larger tumours, there is a greater risk of complications from radiation therapy.
The common side effects of radiation therapy for eye cancer include the following:
- Cataracts. In a cataract the lens of the eye becomes cloudy. People with cataracts will have a cloudy or foggy vision, have trouble seeing at night, or have problems with the glare from the sun. If the cataract is causing major problems with a person’s eyesight, it will be surgically removed.
- Loss of eyelashes and/or a dry eye. These side effects could occur with external-beam radiation therapy and proton-beam radiation therapy.
The following side effects are rare but they can cause a loss of vision:
- Radiation retinopathy: The development of abnormal blood vessels in the retina
- Radiation optic neuropathy: Optic nerve damage
- Neovascular glaucoma: This is a painful condition where new blood vessels develop and block the outflow of fluid from the eye
- Loss of eye: If there is significant damage to the eye from radiation therapy, the eye should be removed.
Laser therapy uses heat in the form of a laser to shrink the tumour. It is also known as thermotherapy or transpupillary thermotherapy (TTT). This treatment has fewer side effects compared to surgery or radiation therapy. Laser therapy could also be combined with radiation therapy.
Chemotherapy is done after surgery to destroy any cancer cells that may remain in the eye. It is administered through a vein in the arm, in the form of a pill or both. Chemotherapy is only used when cancer has become widespread.
Targeted drug treatments focus on specific abnormalities present within the cancer cells for eye cancer.
- Targeted drug treatment blocks the growth of new blood vessels that help cancer grow and survive and thus destroy the cancer cells.
- Targeted therapy drugs are reserved for people with advanced or recurrent eye cancer.
Immunotherapy uses your immune system to fight cancer, but your immune system may not attack the cancer cells because the cancer cells produce proteins that help them to hide from the immune system. Immunotherapy works by interfering with that process.
What are the complications of eye cancer treatment?
Successful treatment of eye cancer is more promising when these cancers are detected early, so it is important to have a regular eye examination. Although eye cancer is rare, it could lead to life-threatening complications and even death if left untreated. The complications include:
- Cancer recurrence or spread
- Emotional and social difficulties
- Treatment side effects
- Vision loss
How can you prepare yourself for the treatment of eye cancer?
- The first and foremost thing that you need to do is keep yourself well informed about your cancer, this improves your quality of life as this can make the disease seem less mysterious and frightening. Information from your doctor and other credible sources can be very helpful in this respect.
- When a person is diagnosed with cancer it hurts their emotional state, so you need to prepare yourself mentally and emotionally. This can be done by being transparent with your family and friends about how you feel, the problems you have been facing so that they can help you in a better way. And as a peer or a family member of the patient, you must support them at all times by listening to them patiently as they are emotionally down.
- You can avail services of a counsellor or attend group therapies consisting of people sharing their past experiences of cancer.
- Writing down about your queries, problems, new symptoms, any physical changes, medications, past medical reports and other important things will help you to clearly express yourself to the doctor.
The checklist given below will help you in planning your treatment in India: