Staging is the process of finding out how far a cancer has spread. The stage (extent) of an eye cancer is one of the most important factors in selecting treatment options and estimating a patient's outlook for recovery and survival (prognosis).

The stage of a cancer is determined from the results of eye exams, imaging tests (ultrasound, CT or MRI scan, etc.) and other tests, which are described in the section, "How is eye cancer diagnosed?"

A staging system is a standardized way for the cancer care team to summarize information about how far a cancer has spread. The most common systems used to describe the stages of eye melanomas are the American Joint Committee on Cancer (AJCC) TNM system and the system used by the Collaborative Ocular Melanoma Study (COMS) group.

AJCC TNM staging system for melanoma of the eye

The TNM system of the American Joint Committee on Cancer (AJCC) is based on 3 key pieces of information:

• T describes the size of the primary tumor and/or whether it has invaded into nearby structures.
• N describes whether the cancer has spread to nearby (regional) lymph nodes (bean-sized collections of immune system cells located throughout the body).
• M indicates whether the cancer has metastasized (spread) to other organs of the body. (The most common site of eye melanoma spread is the liver.)

Numbers or letters appear after T, N, and M to provide more details about each of these factors:

• The numbers 0 through 4 indicate increasing severity.
• The letter X means "cannot be assessed" because the information is not available.

The N and M categories are the same for eye melanomas that start in the iris, ciliary body, or choroid (the 3 parts of the uvea). The T categories, however, are different for these locations.

T categories for iris melanoma

T categories for ciliary body and choroidal melanoma

N categories for iris, ciliary body, and choroidal melanomas

M categories for iris, ciliary body, and choroidal melanomas

Stage grouping

To assign a stage, information about the T, N, and M categories is combined by a process called stage grouping. The stages are described by Roman numerals from I (the least advanced) to IV (the most advanced).

COMS staging of melanoma of the eye

Another staging system that is widely used is one devised by the Collaborative Ocular Melanoma Study (COMS) group, which has done most of the clinical research on how to treat intraocular melanoma. This system divides eye melanomas into small, medium, and large.

Eye melanoma survival rates

Survival rates are a way for doctors to discuss and compare the prognosis (outlook) for patients, based on the stage of the cancer or other traits. For example, the 5-year survival rate refers to the percentage of patients who live at least 5 years after being diagnosed, but many patients live much longer than this.

Overall, about 3 out of 4 people with eye melanoma survive for at least 5 years. Survival rates tend to be better for earlier than for later stage cancers, but accurate survival rates for eye melanomas based on a specific stage are hard to determine because these cancers are fairly rare.

In patients whose cancer is confined to the eye, the 5-year survival rate is about 80%. This is in stark contrast to melanomas that have spread to distant parts of the body, where the 5-year survival rate is about 15%.

There are some important points to keep in mind when looking at such survival rates.

These numbers are derived from patients treated at least several years ago. Improvements in treatment since then mean that the survival rates for people now being diagnosed with these cancers may be higher.

Survival statistics can sometimes be useful as a general guide, but they may not accurately represent any one person's prognosis. A number of factors other than the stage of the cancer may also affect outlook. For example, tumors in which most cancer cells have a spindle-like (long, thin) appearance tend to have better outcome than tumors with more epithelioid (round or square-shaped) cells. Other tumor characteristics, as well as a person's age and general health at the time of diagnosis may also affect prognosis.

Your doctor is likely to be a good source as to whether the numbers above may apply to you, as he or she is familiar with the aspects of your particular situation.

Staging of intraocular lymphoma

Intraocular lymphoma does not have a unique staging system. These cancers may be staged using the system described in our separate document, Non-Hodgkin Lymphoma.

Treatment options are generally based on the type of lymphoma, as well as on whether the lymphoma is limited to the eye or also involves other areas of the body.

Because eye lymphoma is rare, accurate survival statistics for this cancer are hard to find. In one review of patients whose lymphoma was confined to the eye, about half of the patients were still alive 5 years after diagnosis. Unfortunately, in many cases the lymphoma has already reached the brain at the time of diagnosis, in which case the outlook is not as good.

Last Medical Review: 03/03/2009
Last Revised: 05/14/2009