Eye Cancers – Causes, Signs and symptoms

Eye Cancers

Also called: Ocular Cancers

Reviewed By:
Brad Oren, M.D.

Summary

Eye cancers are characterized by an overgrowth of abnormal cells in the eye. The eye is an unusual site for cancer to develop. Its structure and specialized tissues create special challenges in both treating the cancer and preserving vision.

The eye is composed of the globe (eyeball), orbit (the bony canal containing the eyeball) and adnexal (accessory) structures, such as the eyelids and tear glands. This guide focuses on intraocular cancers (cancers of the eyeball) because they have a unique effect on the eye.

Intraocular cancers can be primary eye cancers, which first appear inside the eyeball, or they can be secondary eye cancers, which spread (metastasize) to the eyeball from other locations in the body. Types of primary eye cancer include:

  • Intraocular melanoma. Also called uveal melanoma, intraocular melanoma is the most common primary eye cancer in adults.
  • Primary intraocular lymphoma.  Lymphoma is a form of cancer that may occur in the eye but typically begins in the lymph nodes (bean-sized groups of immune system cells that help ward off infections and cancers). It mainly affects older adults and people with weakened immune systems.
  • Retinoblastoma. Retinoblastoma is a rare cancer that begins in the retina and primarily affects young children.
  • Embryonal medulloepithelioma. Medulloepithelioma is an extremely rare  tumor in the eye that affects young children. Other epitheliomas are brain tumors.

Different types of cancer have different risk factors. For instance, people with blue eyes are more likely to develop intraocular melanoma than those with brown eyes.

All forms of eye cancer are diagnosed after a complete eye examination, which may include a variety of screening tests to determine if cancer is present and has spread to distant sites. Many types of cancer can be diagnosed with a biopsy, but this is extremely difficult to perform on the eye.

When treating eye cancers, physicians weigh such factors as the stage of the cancer and the ability to save the eye or preserve vision. Eye cancer may be treated with numerous therapies, including radiation therapy and chemotherapy  and surgery, which may involve removal of the eye (enucleation). Researchers are investigating new methods of treating eye cancers.

About eye cancers

Eye cancer occurs when certain factors cause the cells in the eye to grow out of control and become malignant. For instance, a weakened immune system increases a person’s risk for developing a cancer called primary lymphoma of the eye. Another eye cancer called retinoblastoma, which typically affects children, is caused by a genetic mutation that can sometimes be inherited from a parent. Unlike normal cells, which divide and grow in an organized manner, cancer cells continue to divide, until they form a growth or tumor (a mass of excess tissue). In some cases, cancer cells in the eye may become invasive, spreading to tissues outside of the eye (metastasis). Any form of cancer in the eye can affect its function and the patient’s ability to see.

The eye is an unusual location for cancer to develop. The structure of the eye and its specialized tissues make it more likely for cancer to develop in only a few parts of the eye. The eye and the surrounding tissues are composed of three main parts:

  • Eye (globe).  The center of the eye is filled with vitreous (a jelly-like substance). The back portion of the eye is lined by the retina, the light sensitive nerve tissue that transmits images to the optic nerve and brain. The uvea is a layer of pigmented tissues that contains three parts:
    • The iris, the colored part surrounding the pupil that regulates the light entering the pupil.
    • The choroid, which lines the eye under the retina and delivers blood to the retina and the front of the eye.
    • The ciliary body, which allows the lens to focus on near and distant objects and produces the aqueous fluid that bathes the front of the eye.

Cancers that affect the eye are called intraocular cancers and most commonly affect the retina or the uvea.

  • Orbit. Contains the tissues surrounding the eye. These tissues include the nerves attached to the eye as well as the muscles that control the movement of the eyeball. Cancers of the orbit are called orbital cancers.
  • Adnexal (accessory) structures. Include the eyelids and tear glands. Cancers that begin in these tissues are known as adnexal cancers.

Cancers of the adnexa and orbit develop from nerve, muscle and skin tissues, just like their counterparts in other parts of the body. For example, a cancer of the eyelid is typically a form of skin cancer. This guide focuses on intraocular cancers, which are unique to the eye.

Intraocular cancers can originate inside the eyeball (primary eye cancers) or spread (metastasize) to the eyeball from other locations in the body (secondary eye cancers). The most common secondary cancers that invade the eye are breast and lung cancers. These cancers frequently spread to the uvea.

Secondary cancers are more common than primary eye cancers, which are considered rare. The American Cancer Society (ACS) estimates that 2,340 new cases of primary or intraocular eye cancer will be diagnosed in 2007. Although primary eye cancers can appear at any age, most cases occur in children under age 6 or adults over age 50. The ACS estimates that 220 Americans will die from eye cancer during 2007.

Types and differences of eye cancers

Eye cancers can be either primary or secondary, depending on where they first occur. Primary eye cancers originate inside the eyeball. Types of primary eye cancer include:

  • Intraocular melanoma. Also called uveal melanoma, intraocular melanoma is the most common primary eye cancer in adults. Typically, melanomas develop from melanocytes, the cells that produce pigment in the skin. When melanoma affects the eyeball, it normally develops in a part of the uvea called the choroid, which contains pigment similar to the melanocytes found in skin. The choroid lines the eyeball and delivers blood to the retina and the front of the eye.

    According to the American Cancer Society (ACS), approximately 90 percent of intraocular melanomas affect the choroid. The remaining 10 percent of intraocular melanomas begin in the iris (the colored portion of the eye that regulates light). These melanomas are sometimes easier to see. They usually appear in a pigmented part of the iris and may exist for several years before they suddenly begin to grow. Intraocular melanomas of the iris are normally slow growing and less commonly invade other regions of the body. For these reasons, individuals with iris intraocular melanomas typically have a better prognosis (predicted outlook for survival).

    Intraocular melanomas are typically composed of two different types of cells. These include elongated spindle cells and round epithelioid cells. Individuals whose tumors are mainly composed of spindle cells generally have a better prognosis because epithelioid cells are more likely to spread (metastasize) to distant sites and become fatal.

  • Primary intraocular lymphoma. Lymphoma is a form of cancer that usually affects older adults and typically begins in the lymph nodes, the bean-sized groups of immune system cells that help ward off infections and cancers. Lymphoma can also arise in other organs, including the eyes. Lymphoma can be divided into two main types: Hodgkin’s lymphoma and non-Hodgkin’s lymphoma. Primary intraocular lymphoma is a type of non-Hodgkin’s lymphoma that usually affects elderly people and individuals with compromised immune systems (e.g., patients with AIDS).

  • Retinoblastoma. Retinoblastoma is a cancer that begins in the retina, the nerve tissue at the back of the eye. It mainly affects infants and children under age 5. However, this rare condition affects only four out of every 1 million children, according to the ACS. It is even rarer in adults. Retinoblastoma that is confined to the retina is called intraocular retinoblastoma. Retinoblastoma that extends beyond the eye, into surrounding tissues or other parts of the body is called extraocular retinoblastoma.

    Most children with retinoblastoma are affected in only one eye. Cases in which both eyes are affected are nearly always caused by an inherited type of the cancer. Children with retinoblastoma are at greater risk for developing a brain tumor (trilateral retinoblastoma) during treatment as well as other types of cancer in later life.

  • Embryonal medulloepithelioma. Medulloepithelioma is an extremely rare tumor in the ciliary body of the eye that occurs in young children. Most medulloepitheliomas are malignant, but they do not usually spread to other parts of the body. Medulloepitheliomas typically cause eye pain and impaired vision. In severe cases, treatment for medulloepithelioma involves surgical removal of the eye (enucleation).

Risk factors and causes of eye cancers

The causes of most forms of eye cancer are not well understood. Continuing research has shown the role of genes in many forms of cancer. For example, retinoblastoma is caused by a genetic mutation, which is either passed on from a child’s parents or occurs during embryonic development. The uncertainty about causes for other forms of eye cancer makes it more difficult to identify risk factors for the condition. However, certain risk factors are associated with each type of eye cancer. These include:

  • Race/ethnicity. Intraocular melanoma is more common in light-skinned people than dark-skinned people.
  • Eye coloration. People with blue irises have an increased risk of developing primary intraocular melanoma.
  • Heredity. Several inherited conditions are related to an increased risk for eye cancers. About 40 percent of retinoblastomas are inherited, according to the American Cancer Society. In addition, the presence of certain conditions can increase the likelihood of intraocular melanoma. A condition called dysplastic nevus syndrome, which causes abnormal skin moles, can increase an individual’s risk of developing eye melanoma. Melanomas of the eye can also run in some families with no history of dysplastic nevus syndrome or oculodermal melanocytosis.
  • Weakened immune system. Having a compromised immune system is a risk factor of developing primary lymphoma of the eye. Therefore, individuals with weakened immune systems, such as people with AIDS or the elderly are more likely to develop eye lymphoma than individuals with healthy immune function.
  • Age. Nearly two-thirds of patients diagnosed with retinoblastoma are under 2 years of age, and 95 percent of retinoblastoma patients are younger than 5. This condition is extremely rare in adults. Age is also considered a risk factor for the development of eye lymphoma, which is more common in elderly people.
  • Exposure to sun. Excessive exposure to sunlight may be a risk factor for eye melanoma. However, this has not yet been proven.
  • Welding. Some evidence indicates that long-term exposure to equipment used in welding increases an individual’s risk of developing eye melanoma. However, this evidence is not conclusive, and further study is needed.

Signs and symptoms of eye cancers

Signs and symptoms of eye cancers may be difficult to distinguish from symptoms for other conditions. Signs and symptoms of  intraocular melanoma, the most common form of adult eye cancer, include:

  • Reduced vision
  • Floaters (spots that drift into the field of vision)
  • Flashes of light
  • Reduction in visual field (the patient loses part of the field of sight)
  • A dark spot on the iris that increases in size

Individuals who experience any of these signs and symptoms should promptly notify their ophthalmologist (a physician who specializes in diseases that affect the eye). Vision trouble is usually the first symptom of intraocular lymphoma. This condition is not usually accompanied by pain and typically affects both eyes.

Vision trouble is usually the first symptom of intraocular lymphoma, a very rare form of eye cancer. This condition is not usually accompanied by pain, and typically affects both eyes.

Signs and symptoms of retinoblastoma, which mainly affects young children, may include:

  • Unusual appearance of the eye, in which the pupil turns white rather than red in response to direct light (leukokoria). This may be visible in an infant after a flash photograph is taken.
  • The eyes look in different directions (strabismus).
  • Vision problems.
  • Eye pain.
  •  The white part of the eye (sclera and conjunctiva) appears red.
  • The pupil does not become smaller when exposed to intense light.

Diagnosis methods for eye cancers

Although different types of eye cancer require different diagnostic tests, diagnosis of all eye cancers typically begins with an eye examination by an ophthalmologist (a physician who specializes in diseases that affect the eye). An ophthalmologistexamining an eye for melanoma will look for enlarged blood vessels around the eye, which can indicate the presence of a tumor (an abnormal mass of tissue) inside the eye. The ophthalmologist will also view the eye with a special instrument called an ophthalmoscope, which allows the detection of a tumor or other abnormality. However, other tests are needed to confirm a diagnosis. These may include:

  • Ultrasound. A test that uses high-frequency sound waves to echo off a tumor and create a pattern. Because melanomas have a specific appearance on ultrasound, this test is often heralded as the best test for diagnosing melanomas of the eye prior to surgery. In fact, ultrasound allows physicians to confirm a diagnosis of eye melanoma in more than 80 percent of cases.
  • Fluorescein Angiography. A procedure in which fluorescent dye is injected into the bloodstream and images of the back of the eye are captured using a special light that causes the dye to glow. Angiography may allow the physician to identify and rule out other eye conditions although it is not particularly useful in diagnosing eye melanomas.

Although biopsies are recommended for confirming most cancer diagnoses, they are not generally used to diagnose eye cancers. During a biopsy, a tiny needle is passed into the eye, and tumor cells are collected through a small syringe. Eye biopsies are difficult to perform and the risk of damaging the eye or inadvertently spreading the tumor outside the eye is too great.

If intraocular melanoma is found, the physician may order the following tests to determine if the cancer has spread (metastasized) to other areas of the body:

  • Chest x-ray. Sometimes the physician will order a chest x-ray to see if the cancer has spread to the lungs. This is highly unlikely unless the cancer has reached an advanced stage.
  • CAT (computed axial tomography) scan. This x-ray procedure produces numerous cross–sectional images of the body to help determine if cancer has spread to distant sites. CAT scans take longer than x-rays and require the patient to lie still on a table for the duration of the procedure. Before a CT scan, patients will often be injected with a radiocontrast agent, or dye, which outlines the structures in the body more clearly.
  • MRI (magnetic resonance imaging). This procedure uses strong magnets and radio waves to produce cross-sectional images of the body, much like a CAT scan. In addition, MRIs can also produce images that are parallel with the length of the body, which can be useful in identifying the spread of cancer. MRI requires the patient to lie inside a tube-like structure, and a contrast material or dye may or may not be administered intravenously in the arm.

During an eye examination for intraocular lymphoma, the ophthalmologist will look for cloudiness in the vitreous, the gel that fills the interior of the eye. If this cloudiness does not dissipate with treatments commonly prescribed for the inflammation called uveitis (a noncancerous problem), the ophthalmologist may order an ultrasound, MRI or (rarely) CAT scan. The following tests may also be ordered:

  • Vitrectomy.  A type of biopsy in which a needle-like instrument is used to remove a sample of the vitreous fluid or a piece of the tumor is removed through a small incision and examined.
  • Spinal tap (also called lumbar puncture). A needle is inserted into the lower back to obtain a small sample of the fluid that surrounds and protects the brain and spinal cord (cerebrospinal fluid). The cerebrospinal fluid is then examined for lymphoma cells under a microscope because lymphoma of the eye can spread to the brain.

A retinoblastoma examination will include a detailed family history because approximately 40 percent of these cancers are inherited. If a parent is known to have the genetic defect, a specialized blood test can identify the gene in an infant in the first months of life. Infants at risk for retinoblastoma will have regular eye exams during infancy.

During the exam, the ophthalmologist will view the retina with special instruments and magnifying lenses. The child may be put to sleep with general anesthesia so the ophthalmologist can examine the affected eye(s) more carefully. Imaging tests such as ultrasound, CT scans and MRIs can also be used to diagnose retinoblastoma. Children may be sedated for these tests when they require the patient to remain still for an extended period of time.

In addition, the oncologist may occasionally order radionuclide imaging, which shows whether the cancer has invaded the skull and other bones. During this procedure, radioactive dye injected into the patient accumulates in any diseased bones in the skeleton.  These areas of diseased bone appear dense and gray on the bone scan, indicating possible areas of metastasis. Physicians may then order additional tests to determine if the areas are secondary cancers or other conditions.

Treatment and prevention of eye cancers

After eye cancer is detected and staged,  the patient’s cancer care team will devise a treatment plan that focuses on the type, stage and location of the cancer, as well as the patient’s overall health status. The treatment choice also involves whether or not it can preserve the patient’s vision. Intraocular cancers are rare, so the patient may choose to seek a second opinion from a physician who specializes in cancers of the eye. Treatment options for eye cancers include:

  • Surgery. Surgery is used to treat some patients with intraocular melanomas and children with retinoblastomas. Common surgical procedures for these cancers  include:
    • Iridectomy. Procedure to remove part of the iris. This technique is typically used for very small iris melanomas.
    • Iridotrabeculectomy. Procedure to remove part of the iris and some of the tissue that drains the aqueous fluid. This is another techniques used for small iris melanomas.
    • Iridocyclectomy. Procedure to remove part of the iris and the ciliary body. This operation is also used to treat small iris melanomas.
    • Enucleation. Procedure to remove the entire eyeball. Enucleation is the standard surgical treatment for retinoblastoma of one eye. It is also the preferred treatment for large melanomas because other treatments for these tumors would also destroy the patient’s vision. The eye is replaced with a prosthetic version, and the muscles are reattached to allow some normal movement.
  • Radiation therapy. High-energy radiation used to kill or shrink cancer cells. The main advantage of radiation therapy, which can often preserve part of the patient’s vision, is that it also preserves the structure of the eye. However, it can damage tissue around the eye and may lead to the eventual development of cataracts, a cloudiness on the eye’s lens. Types of radiation therapy include external beam radiation andbrachytherapy. 

    External beam radiation may be used to treat intraocular lymphoma. Brachytherapy involves surgical placement (and later removal) of radioactive seeds close to the tumor. Brachytherapy, which typically cures 90 percent of small tumors, is the most common form of radiation used for eye melanomas. It is also used to treat retinoblastomas.
  • Laser therapy. This type of therapy burns tissue with a high-energy, highly focused beam of light. Laser therapy can be effective in treating tiny retinoblastomas and small melanomas of the eye. Even though the laser beam can accurately focus only on the cancer cells, patients still experience some visual loss after laser therapy. Patients usually require several laser treatments, which are typically administered six to eight weeks apart.
  • Thermotherapy. Used to treat retinoblastoma, thermotherapy heats the eye with infrared lasers. Thermotherapy may be the only form of treatment for small tumors in certain locations. Similar to standard laser therapy, thermotherapy is generally administered while the patient is under anesthesia. Patients typically require three treatments over the course of three months.
  • Cryotherapy (also called cryosurgery and cryocoagulation). Cryotherapy relies upon extreme cold to destroy small retinoblastoma tumors. After the patient is put to sleep with anesthesia, a low-temperature probe is placed next to the tumor on the eye’s surface. The extreme temperature of the probe kills the cancer cells. Cryotherapy may cause temporary swelling of the eye and eyelid, and usually must be repeated several times.
  • Chemotherapy. This treatment uses powerful drugs to kill cancer cells. These drugs are typically administered either intravenously or orally. After the drugs enter the patient’s bloodstream, they begin to spread throughout the body. Chemotherapy is an efficient method to treat intraocular lymphoma. Depending on the lymphoma’s type and stage, chemotherapy may be used alone or it may be combined with radiation therapy.

    However, relatively few drugs have proven beneficial for treating intraocular melanoma. Chemotherapy is used to treat melanomas that have spread from the eye to other areas of the body. Chemotherapy may also be used to treat children with retinoblastoma in both eyes in an attempt to shrink the tumors. It is also used when retinoblastoma has spread to distant sites. However, this type of cancer tends to become resistant to chemotherapy over time.

Patients who receive treatment for eye cancer will typically attend follow-up examinations every three months. Certain tests, such as MRI, may be performed to ensure that the cancer has not reappeared or spread (metastasized) to other areas of the body. Children with retinoblastoma may be at risk for developing other cancers, including brain tumors. They may require regular MRIs or other tests to monitor for a new appearance of cancer. Patients are encouraged to immediately report any new symptoms to their physician. New symptoms can indicate recurrence of a cancer or side effects from treatment.

Eye cancer patients may also face loss of vision or vision impairment and cosmetic problems associated with their treatment. When an eye is removed through enucleation, a prosthesis is used to replace it. In addition, some treatments may cause a sagging or caved-in appearance of the eye, which can also be treated.

To date, there is no known method of preventing eye cancers. People may be able to reduce their risk by limiting their exposure to direct sunlight and wearing wrap-around sunglasses with 99 to 100 percent UVA and UVB absorption. However, there are no steps that a parent or child can take to reduce a child’s risk of developing retinoblastoma.

Ongoing research regarding eye cancer

Researchers are investigating new methods for treating eye cancers. These include:

  • Collaborative Ocular Melanoma Study (COMS). This study involves the results of clinical trials conducted by 43 medical centers. The pooled resources have been used to investigate treatments for choroidal melanoma.
  • Biological therapy (also called immunotherapy). Clinical trials are investigating the effects of cytokines, vaccines and other biological therapies on melanomas and lymphomas. Although most of these clinical trials involve patients with skin melanomas and lymphomas that primarily appear in the lymph nodes, the results of these studies may help treat patients with the intraocular version of these conditions as well.
  • Radiation therapy. Researchers are working to improve external beam radiation therapy to treat eye cancer. Technology has focused on gamma knife treatment, proton beam therapy and intensity-modulated conformal therapy. These methods offer more precise beams of radiation to destroy cancer cells while protecting healthy tissue.
  • Genetics. Scientists are exploring the genetic causes of melanoma. This may allow them to develop melanoma screening tests and gene therapies to cure the condition.

Staging eye cancers

The prognosis (predicted outlook for survival) of eye cancer depends on the cancer’s stage, or how widespread it is in the body. A staging system devised by the Collaborative Ocular Melanoma Study group is probably the most widely used staging system for intraocular melanomas. This system categorizes melanomas by their size:

TypeThicknessDiameter
Large0.4 inch (10 millimeters) or greater0.6 inch (16 mm) or greater
Medium0.1 to 0.4 inch
(2.5 to 10 mm)
0.2 to 0.6 inch
(5 to 16 mm)
Small0.04 to 0.1 inch
(1 to 2.5 mm)
0.2 inch (5 mm)

Another staging system for cancer is the TNM system, which was developed by the American Joint Committee on Cancer (AJCC):

  • “T” describes the size of the tumor.
  • “N” describes whether the cancer has spread to surrounding lymph nodes (bean-sized groups of immune system cells that help ward off infections and cancers).
  • “M” describes whether or not the cancer has spread or metastasized to distant organs.

Information about the T, N and M categories is combined by a process called stage grouping to assign a stage to the eye cancer. The stages are labeled in order of severity, using Roman numerals and the letters “A” and “B.”

The five–year survival rate for small eye melanomas that are detected and treated early (in stage I or II) exceeds 90 percent. For larger eye melanomas, the rate is about 60 percent. Approximately half of patients with stage IV eye melanoma die within a year.

There is no unique system used to stage intraocular lymphomas.  However, this type of cancer may be staged using the system for non-Hodgkin’s lymphoma.

Physicians use the Reese-Ellsworth Staging System to stage retinoblastoma. This staging system is divided into five groups. The higher the group number, the less likely the patient will maintain vision.

The ganglion cells of the retina become the optic nerve at the optic disk. Because physicians cannot directly measure retinoblastomas, they compare the tumor’s size with the size of the optic disk, which is typically about 1/16 inch (1.5 mm). For instance, a tumor estimated to be four times the size of the optic disk (4 DD or 4 disk diameters) would be approximately 4/16 inch (6 mm) in diameter. The front and back halves of the eyeball are divided by an imaginary line called the equator.

The staging system for retinoblastoma is as follows:

  • Group 1 (vision maintenance is very favorable):
    • One or more tumors, smaller than 4 DD, all behind or at the equator
  • Group 2 (vision maintenance is favorable):
    • One or more tumors, between 4 DD and 10 DD, all behind or at the equator
  • Group 3 (vision maintenance is doubtful):
    • Any tumor located in front of the equator
    • A single tumor, larger than 10 DD, located behind the equator
  • Group 4 (vision maintenance is unfavorable):
    • Multiple tumors, some exceeding 10 DD
    • Any tumor that extends toward the ora serrata (the retina’s front edge)
  • Group 4 (vision maintenance is very unfavorable):
    • Tumors affecting over half the retina
    • Vitreous seeding (the spread of tumors into the vitreous (the gel that fills the interior of the eye)

To simplify the staging process, physicians sometimes use the ABC Classification system:

GroupDescription
ASmall tumors (approximately 0.1 inch [3 mm]) that are confined to the retina
BLarger tumors that are confined to the retina
CLocalized vitreous seeding or seeding under the retina less than 0.2 inches (6  mm) away from the initial tumor
DWidespread subretinal or vitreous seeding, possible total retinal detachment
ENo visual potential, the eye cannot regain vision

Questions for your doctor regarding eye cancer

Preparing questions in advance can help patients have more meaningful discussions with their physicians about their conditions. Patients or parents may wish to ask their doctors the following questions related to eye cancer:

  1. What tests will be done to diagnose my eye cancer?
  2. What type of eye cancer do I have?
  3. Did the cancer start in my eye or another part of my body?
  4. What are the treatment options for my type of cancer?
  5. What are the risks associated with these treatments?
  6. What is my prognosis with this type and stage of cancer?
  7. How will I know if my eye cancer is getting worse?
  8. If my baby has retinoblastoma, should my older children be tested for it?
  9. What long-term effects can retinoblastoma treatment have on my child?
  10. Can my eye cancer recur after treatment? In one or both eyes?
  11. What lifestyle changes do I need to make based on my eye cancer and treatment?
  12. Are there any symptoms I can watch for that might indicate recurrence?
  13. How much experience do you have treating eye cancer?
  14. Am I a candidate for any clinical trials?
  15. Can you recommend a support group for eye cancer patients?
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