Eye Cancer

Eye cancer is a general term used to describe many types of tumors that occur in various parts of the eye. It occurs when cells in or around the eye change and grow uncontrollably, forming a mass called a tumor. A tumor may be benign (noncancerous) or malignant (cancerous, meaning cells can spread to other parts of the body). Cancer that forms in the eyeball is called an intraocular malignancy.

Medical doctors who specialize in the diseases and function of the eye are called ophthalmologists (or “eye MDs”). These doctors can diagnose and treat intraocular melanoma. Optometrists are another type of eye doctor. They prescribe eyeglasses and contact lenses. They are not medical doctors and are not trained to treat intraocular cancer.

Parts of the eye

The eye is the organ that collects light and sends messages to the brain to form a picture. The three main parts of the eye are:

• Eyeball
• Orbit (eye socket)
• Adnexal (accessory) structures (such as the eyelid and tear glands)

The outer part of the eye is made up of the sclera, retina, and uvea. The sclera is the outer wall of the eyeball. The retina is a thin-layered structure that lines the eyeball and sends information from the eye to the brain. The uvea nourishes the eye. Both the retina and the uvea contain blood vessels. The uvea consists of the following:

• Iris: The colored part of the eye that controls the amount of light entering the eye
• Ciliary body: Muscular tissue that produces the watery fluid in the eye and helps the eye focus
• Choroid: The layer of tissue underneath the retina that contains connective tissue and melanocytes and nourishes the inside of the eye; the choroid is the most common site for a tumor.

Types of intraocular cancer

The most common intraocular cancer in adults is uveal metastases, which is cancer that has spread to the uvea from another place in the body; this is called secondary cancer. This article is about primary intraocular cancer, meaning that the tumor started in the eye, not somewhere else in the body.

Melanoma is the most common type of primary intraocular cancer in adults. It begins when pigmented (colored) cells in the eye called melanocytes grow uncontrollably. Intraocular melanoma is also called uveal melanoma.

Other, less common types of an intraocular tumor include:

Intraocular lymphoma is lymphoma that begins in the eyeball. This condition is rare and can be difficult for doctors to diagnose. Many doctors consider intraocular lymphoma to be a type of central nervous system lymphoma. Most intraocular lymphomas are non-Hodgkin lymphoma.

Retinoblastoma is a rare form of childhood eye cancer.

Hemangioma is a benign vascular tumor of the choroid and retina.

Other, rare cancers of the eye include the following:

Conjunctival melanoma is a tumor of the conjunctiva (a membrane that lines the eyelid and eyeball). If it is not treated, it can spread to the lymph nodes (tiny, bean-shaped organs located throughout the body that fight disease). A conjunctival melanoma tends to recur (come back after treatment) on the eye's surface and looks like dark spots on the eye. Doctors often perform a biopsy (removal of a sample of the tissue for examination under a microscope) on a spot that appears to be conjunctival melanoma.

Eyelid carcinoma (basal or squamous cell) is a variation of skin cancer. This tumor may be surgically removed and is usually not dangerous if it is treated early.

Lacrimal gland tumor is a benign or malignant tumor of the glands that produce tears.

Symptoms and Signs

People with eye cancer may experience the following symptoms or signs. Sometimes people with eye cancer do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not cancer. If you are concerned about a symptom or sign on this list, please talk with your doctor.

• Having trouble seeing
• Losing part of the field of vision
• Seeing flashes of light
• Seeing spots, squiggly lines, or floating objects (floaters)
• Having a dark spot on the iris. Unlike choroidal and ciliary body melanoma, iris melanoma can sometimes be seen because it looks like dark spots on the eye.

Stages and Grades

One tool that doctors use to describe the stage is the TNM system. This system judges three factors: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to other parts of the body. The results are combined to determine the stage of cancer for each person. The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.

In addition to staging, doctors may use other information to help figure out prognosis and the risk of the cancer spreading. These findings may also be included on the pathology report and include:

• Alterations to the cancer cell's chromosomes (as described in Diagnosis); for example, one copy of chromosome three, called monosomy 3, can indicate a higher risk of the cancer spreading
• Gene expression profiles (as described in Diagnosis); these tests classify a tumor into class I (at lower risk for metastasis) and class II (at higher risk for metastasis)
• Other characteristics of the cancer cells, such as the grade (see below for more details)

TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:

• How large is the primary tumor, and where is it located? (T, tumor)
• Has the tumor spread to the lymph nodes? (N, node)
• Has the cancer spread to other parts of the body? (M, metastasis)

Some ophthalmologists may not use the TNM system to stage an intraocular tumor. However, they still consider the size of the tumor and how it is affecting a person's vision when deciding on a treatment plan.

Specific information about the TNM system is listed below. In eye cancer, T for an iris melanoma is described differently than T for choroidal and ciliary body melanomas. N and M are described the same for iris, choroidal, and ciliary body melanomas.

Tumor. Using the TNM system, the “T” plus a letter and/or number (0 to 4) is used to describe the size and location of the tumor. Some stages are also divided into smaller groups that help describe the tumor in even more detail. The following classifications are the same for any type of intraocular melanoma:

TX: The primary tumor cannot be evaluated.

T0: There is no tumor in the eye.

Iris melanoma

An iris tumor is classified as T1, T2, T3, or T4. Some stages are divided into smaller groups that help describe the tumor in even more detail.

T1: The tumor is limited to the iris.

T1a: The tumor is in one quadrant (one-fourth) or less of the iris.

T1b: The tumor is in more than one quadrant of the iris.

T1c: The tumor is only in the iris, but there is melanomalytic glaucoma. This means that a buildup of certain cells in the eye blocks the flow of fluid in the eye, causing pressure.

T2: The tumor has joined or grown into the ciliary body and/or choroid.

T2a: The tumor has joined or grown into the ciliary body and/or choroid with melanomalytic glaucoma.

T3: The tumor has joined or grown into the ciliary body and/or choroid and extends to the sclera (outer wall of the eyeball).

T3a: The tumor has joined or grown into the ciliary body and/or choroid and extends to the sclera in association with melanomalytic glaucoma.

T4: The tumor has spread to the outside of the eyeball, the optic nerve, or to the eye socket. This is called extraocular extension.

T4a: The tumor has spread is less than 5 millimeters (mm) outside of the eye.

T4b: The tumor has spread more than 5 mm outside of the eye.

Ciliary body and choroid melanoma

A tumor in the ciliary body and choroid is also classified as T1, T2, T3, or T4 based on the size of the tumor, which is measured in optic disc diameters or millimeters (mm). The tumor is measured for both width and height (also called thickness). A tumor is given a classification according to the table below, based on its width and height.

Your doctors may use and refer to this classification, called a category, even more than the stage. This is because the size and thickness of the tumor (the T) is most important for finding out a patient's prognosis.

Size Category Classification Table for Ciliary Body and Choroid Melanoma

Thickness (mm)	Category
Thicker than 15 mm					4	4	4
12.1 to 15.0				3	3	4	4
9.1 to 12.0		3	3	3	3	3	4
6.1 to 9.0	2	2	2	2	3	3	4
3.1 to 6.0	1	1	1	2	2	3	4
Less than 3.0	1	1	1	1	2	2	4
Largest basal diameter (mm)	Less than 3.0 mm	3.1 to 6.0 mm	6.1 to 9.0 mm	9.1 to 12.0 mm	12.1 to 15.0 mm	15.1 to 18.0 mm	Larger than 18.0 mm

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois.

T1: The tumor is size category 1.

T1a: The tumor is size category 1 and does not involve the ciliary body or other parts of the eye.

T1b: The tumor is a category 1 and involves the ciliary body.

T1c: The tumor is size category 1 that does not involve the ciliary body. But, there is a very small area (5 mm or less in diameter) of visible spread beyond the eyeball (called extraocular spread).

T1d: Thetumor is a size category 1 that involves the ciliary body with extraocular spread less than 5 mm.

T2: The tumor is size category 2.

T2a: The tumor is size category 2 and does not involve the ciliary body or other parts of the eye.

T2b: The tumor is size category 2 and involves the ciliary body.

T2c: The tumor is size category 2 that does not involve the ciliary body. But, there is a very small area (5 mm or less in diameter) of visible spread beyond the eyeball.

T2d: The tumor is size category 2 that involves the ciliary body with extraocular spread less than 5 mm.

T3: The tumor is size category 3.

T3a: The tumor is size category 3 and does not involve the ciliary body or other parts of the eye.

T3b: The tumor is size category 3 and involves the ciliary body.

T3c: The tumor is size category 3 that does not involve the ciliary body. But, there is a very small area (5 mm or less in diameter) of visible spread beyond the eyeball.

T3d: The tumor is size category 3 that involves the ciliary body with extraocular spread less than 5 mm.

T4: The tumor is size category 4.

T4a: The tumor is size category 4 and does not involve the ciliary body or other parts of the eye.

T4b: The tumor is size category 4 and involves the ciliary body.

T4c: The tumor is size category 4 that does not involve the ciliary body. But, there is a very small area (5 mm or less in diameter) of visible spread beyond the eyeball.

T4d: The tumor is size category 4 that involves the ciliary body with extraocular spread less than 5 mm.

T4e: The tumor is any size category with extraocular spread of more than 5 mm in diameter.

Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the eye are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes. N is described the same for melanomas of the iris, ciliary body, and choroid.

NX: The regional lymph nodes cannot be evaluated.

N0 (N plus zero): There is no regional lymph node metastasis.

N1: There is regional lymph node metastasis.

Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread from the eye to other parts of the body. M is described the same for iris, ciliary body, and choroidal melanomas.

MX: Distant metastasis cannot be evaluated.

M0 (M plus zero): There is no distant metastasis.

M1: There is metastasis to other parts of the body.

M1a: There is metastasis to other parts of the body and the largest metastasis is 3 centimeters (cm) or less in diameter.

M1b: There is metastasis to other parts of the body and the largest metastasis is between 3.1 cm and 8 cm in diameter.

M1c: There is metastasis to other parts of the body and the largest metastasis is larger than 8 cm in diameter.

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications.

Stage I: The tumor is size category 1 and does not involve the ciliary body or other parts of the eye, nor has it spread to the regional lymph nodes or to other areas of the body (T1a, N0, M0).

Stage IIA: The tumor is either a size category 1 that may or may not involve the ciliary body, with or without extraocular extension, or it is a size category 2 that does not involve the ciliary body. There is no spread to the regional lymph nodes or to other areas of the body (T1b, T1c, T1d, or T2a; N0, M0).

Stage IIB: The tumor is either a size category 2 that involves the ciliary body but has not spread beyond the eyeball, or it is a size category 3 that has not spread to the ciliary body or eyeball. It has not spread to the regional lymph nodes or to other areas of the body (T2b or T3a; N0, M0).

Stage IIIA: Stage IIIA describes any one of these conditions:

• A tumor of size category 2 with extraocular spread to a diameter of 5 mm or less, with or without ciliary body involvement that has not spread to the lymph nodes or to other parts of the body (T2c or T2d, N0, M0)
• A tumor of size category 3 that may or may not involve the ciliary body, with or without extraocular spread to a diameter of 5 mm or less, but hasn't spread to the lymph nodes or to other parts of the body (T3b or T3c, N0, M0)
• A tumor of size category 4 that does not involve the ciliary body and has not spread to the lymph nodes or to other parts of the body (T4a, N0. M0)

Stage IIIB: Stage IIIB describes any one of these conditions:

• The tumor is a size category 3 with ciliary body involvement and extraocular spread that has not spread to the lymph nodes or to other parts of the body (T3d, N0, M0).
• The tumor is a size category 4 with or without ciliary body involvement that may or may have spread outside the eyeball. It has not spread to the regional lymph nodes or to other areas of the body (T4b or T4c, N0, M0).

Stage IIIC: The tumor is a size category 4 that involves the ciliary body and has spread outside the eyeball. However, it has not spread to the regional lymph nodes or to other areas of the body (T4d or T4e; N0, M0).

Stage IV: This stage describes a tumor of any size that has spread to the lymph nodes and/or to other parts of the body outside of the eye (any T, N1, M0; or, any T, any N, M1).

Recurrent: Recurrent cancer is cancer that has come back after treatment. It may return in the eye or in another part of the body. If there is a recurrence, the cancer may need to be staged again (called re-staging) using the system above.

Histopathology and grading

After a biopsy or when the tumor is surgically removed, doctors may look at the types of cells that are in the tumor; this is called histopathology. Three types of histopathology patterns may be present in the tumor:

• Spindle cell melanoma (the cells are longer and tapered at the ends)
• Epithelioid melanoma (the cells are oval-shaped)
• Mixed cell melanoma (both spindle and epithelioid)

Generally, a tumor made up of spindle cells has a better prognosis than a tumor made up of epithelioid cells. The tumor is given a grade (G) to describe the composition of its cells. A lower grade generally indicates a better prognosis than a higher grade.

GX: The grade cannot be evaluated.

G1: A spindle cell melanoma

G2: A mixed cell melanoma

G3: An epithelioid melanoma