Ocular cancers are rare malignancies that develop in or around the eye. There are many different types of ocular cancers that vary based on the cells they develop from. 

The eye is a sensory organ that allows us to see by reacting to light. Light passes through the cornea (the clear, front layer of the eye) and enters the eye through an opening called the pupil (the black centre of the eye). The amount of light received by the pupil is controlled by the iris (the coloured portion of the eye). This light is then passed through the lens (the clear, inner portion of the eye) and works together with the cornea to focus light onto the retina (a layer of tissue at the back of the eye that is sensitive to light). The retina then activates photoreceptors (image forming cells) to convert the light to electrical impulses that travel to the brain via the optic nerve, which is then converted into an image.  

Most ocular cancers are more common in males, and tend to develop over the age of 55. However, anyone can develop these diseases.

Types of Ocular Cancers

There are several different types of ocular cancers, which are categorised based on the different cells they develop from.

Ocular Melanoma

Ocular melanoma, or eye melanoma, is a type of melanoma that occurs in the eye. Melanomas develop from melanocytes, which are the cells that produce pigment, generally in the skin. However, they can also develop in the eye and possibly other parts of the body. 

For more information on ocular melanoma, please refer to the Rare Cancers Australia Melanoma (Ocular) page.

Retinoblastoma

Retinoblastoma is a rare type of ocular cancer that develops in the retina of the eye. It is a type of blastoma, which are cancers that develop in precursor cells, most often in children. It can occur in one eye (unilateral retinoblastoma, usually non-hereditary), or in both eyes (bilateral retinoblastoma, often hereditary).

For more information on retinoblastoma, please refer to the Rare Cancers Australia Retinoblastoma page.

Ocular Lymphoma

Ocular lymphoma is a rare type of cancer that develops from the lymphatic system, a network of tissues and organs that help our bodies fight infection and disease. Ocular lymphomas can be divided into two categories.

Primary Intraocular Lymphoma (PIOL)

Primary intraocular lymphoma (PIOL) is a rare subtype of ocular cancer that develops from lymphatic cells inside of the eye. While there are no lymphatic cells naturally in the eye, lymphomas cells may invade portions of the eye and develop here. This type of cancer has been linked to people who have a weakened immune system, including people with acquired immunodeficiency syndrome (AIDS), people who have had an organ transplant, and elderly people. PIOL is often aggressive, and may not have as good of a prognosis as other types of ocular cancer.

Ocular Adnexal Lymphoma

Ocular adnexal lymphoma, also known as mucosa-associated lymphoid tissue (MALT) lymphoma of the eye,  is a very rare form of ocular cancer that develops in the tissue surrounding the eye, including the eyelids, conjunctival sac, and lacrimal gland. These tumours can be aggressive, but can have a good prognosis when found early.

Medulloepithelioma of the Ciliary Body

Medulloepithelioma of the ciliary body is a very rare form of ocular cancer that develops in the ciliary body, a portion of the eye wall that changes the shape of the lens when the eye focuses. Unlike most ocular cancers, this subtype is slightly more common in females, and is generally diagnosed in children between the ages of two and five. Medulloepitheliomas of the ciliary body are not often aggressive, and generally have a good prognosis.
Medulloepitheliomas of the ciliary body should not be confused with medulloepitheliomas of the brain.

Squamous Cell Cancer of the Conjunctiva 

Squamous cell cancer of the conjunctiva is a rare form of ocular cancer that develops in the conjunctiva, a thin, clear, mucinous membrane that covers the eye and lines the eyelid. It is more common in males, and tends to be diagnosed between the ages of 50-75. Squamous cell cancer of the conjunctiva is generally not aggressive, and can have a good prognosis. 

Lacrimal Gland Cancer

Lacrimal gland cancer is a rare type of ocular cancer that develops in the lacrimal glands, the small, tear-shaped gland in each eye that secretes liquid (also known as tears) to clean, protect, and lubricate the eyes. These cancers are often aggressive, and may not have as good of a prognosis as other types of ocular cancers.

Orbital Rhabdomyosarcoma

Orbital rhabdomyosarcomas are a rare form of ocular cancer that develops in the muscles of the eye. While rhabdomyosarcomas are the most common form of soft tissue sarcoma in children and adolescents, orbital rhabdomyosarcoma is considered to be rare. They are more common in males, and are generally diagnosed between the ages of five and seven. Orbital rhabdomyosarcomas are often aggressive, and may not have as good of a prognosis as other types of ocular cancers.

For more information on rhabdomyosarcomas, please refer to the Rare Cancers Australia Rhabdomyosarcoma page.

Cancers of the Eyelid

Cancers of the eyelid are rare, and are often forms of skin cancer. The two most common forms are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). When these tumours are found, they are generally treated like any other skin cancer.

For more information on skin cancer, please refer to the Rare Cancers Australia Skin Cancer page.

Adenocarcinoma of the Eye and Adnexa

Adenocarcinomas (cancers arising from mucus-producing glands) of the eye and adnexa are a very rare form of ocular cancer that generally develop in the retina or ciliary body. This type of cancer is slightly more common in females, and often responds poorly to radiation therapy. Because of how rare these cancers are, there has been limited research done into the aggressiveness and prognosis of this disease. 

Treatment 

If an ocular cancer is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. 

There are two primary staging and grading systems used in the classification of ocular cancers – The International retinoblastoma staging system and the TMN system.

The International Classification for Intraocular Retinoblastoma (ICIR)

The international classification for intraocular retinoblastoma (ICIR) divides intraocular cancer into five groups based on the characteristics of the tumour. These groups include:

• Group A: very low risk, very small tumours not located near critical structures, confined to retina.
• Group B: low risk, small tumours close to critical structures, confined to retina.
• Group C: moderate risk, well-defined tumours with small amounts of spread under the retina (subretinal seeding) or into the vitreous (gel-like substance in the eye) (vitreous seeding).
• Group D: High risk, large tumours with widespread subretinal and/or vitreous seeding, retina may become detached from the back of the eye.
• Group E: Very high risk, very large tumours extending near the front of the eye, may cause bleeding or glaucoma (high intraocular pressure).

TNM Staging System

The TNM system can also be used to classify a ocular cancers. The TNM system is comprised of:

• T (tumour) indicates the size and depth of the tumour. 
• N (nodes) indicates whether the cancer has spread to nearby lymph nodes. 
• M (metastasis) indicates whether the cancer has spread to other parts of the body. 

This system can also be used in combination with a numerical value, from stage 0-IV: 

• Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue. 
• Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
• Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer. 
• Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer. 
• Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.

Cancers can also be graded based on the rate of growth and how likely they are to spread: 

• Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour. 
• Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.  
• Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.  

Treatment options

Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.  

Treatment is dependent on several factors, including location, stage of disease and overall health. 

Treatment options for retinoblastomas may include:

• Surgery, potentially including:
  • Iridectomy, which is the partial removal of the iris.
  • Iridocyclectomy, which is the partial removal of the iris and the ciliary body.
  • Endoresection/transscleral resection, which is the removal of the tumour only in the ciliary body or the choroid.
  • Enucleation, which is the removal of the eye.
  • Orbital exenteration, which is removal of the eye and some surrounding tissue. 
• Chemotherapy, potentially including:
  • Ophthalmic artery infusion chemotherapy.
  • Intravitreal chemotherapy.
  • Intrathecal chemotherapy. 
• Radiation therapy.
• Laser therapy (transpupillary thermotherapy).
• Laser therapy (photocoagulation).
• Photodynamic therapy.
• Cryotherapy.
• Targeted therapy.
• Clinical trials.
• Palliative care.

For more information on the treatment options, please refer to the Rare Cancers Australia treatment options page.

Risk factors 

While the cause of ocular cancer remains unknown, the following factors may increase the likelihood of developing the disease:

• Family history of ocular cancers
• Genetic mutation in the RB1 (retinoblastoma protein 1) gene.
• Gender and age (being male and being over 50).
• Having pale skin. 
• Having a light eye colour, such as blue or green.
• A family history of melanoma.
• Having a growth on or in the eye.
• Certain skin conditions, such as dysplastic naevus syndrome.
• BAP1 cancer syndrome.
• Having a weakened immune system, such as from:
  • Having acquired immunodeficiency syndrome (AIDS).
  • Having had an organ transplant.
  • Being elderly.

Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned. 

Early symptoms 

The symptoms of an ocular cancer may include:

• The pupil appears white instead of red when light is shone into it (e.g., in photographs)
• Pain and/or redness in the eye.
• Eyes that suddenly start looking in different directions (crossed eyes or lazy eyes).
• Infection around the eye.
• Abnormally large eyeball.
• Cloudiness in the iris and pupil.
• Poor and/or blurred vision in one or both eyes.
• Loss or peripheral vision.
• Discoloured patches in the sclera. 
• Seeing ‘wavy lines’ in your vision.
• Vision flashes.
• A change in pupil shape.
• Drooping eyelid.
• Bulging of the eye.
• A lump in or around the eye.
• Feeling that something is in your eye.
• White, painless growth on the surface of the eye.

Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned. 

Diagnosis/diagnosing 

If your doctor suspects you have an ocular cancer, they will order a range of diagnostic tests to confirm the diagnosis, and refer you to a specialist for treatment.  

Imaging & blood tests 

The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), and/or ultrasound, depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions. 

Eye tests 

Your doctor may request a variety of eye tests to check for abnormalities in your eye. One of these tests is called an ophthalmoscopy (fundoscopy), which involves using eye drops to widen your pupil and then looking into a large microscope. This option is beneficial as you may not require a biopsy after this test.

Another test, called a fluorescein angiography, examines the blood vessels and blood flow in the eye. This procedure is done by injecting a fluorescent dye into the bloodstream, which travels to the eye. A special camera is used to determine if there are any blocked or leaking vessels in the eye.

The doctor may also request an electroretinography, which measures small electrical signals given off by the eye when exposed to different types of light. This test can be used to measure the effectiveness of the retina during and/or after treatment.

Biopsy 

In few instances, a biopsy may be required if the previous measures have come back inconclusive. In a biopsy, a tissue sample will be removed using a needle, and is then sent to a lab for analysis.

Prognosis (Certain factors affect the prognosis and treatment options) 

While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage ocular cancers have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis. 

References 

• Cancer Research UK
• Cedars-Sinai
• Radiopaedia - Medulloepithelioma

^{Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.}