Metastatic Uveal Melanoma: What to Expect

How Does Metastatic Uveal Melanoma Spread?

Metastatic uveal melanoma spreads by traveling through the blood and forming a tumor in a different part of the body. Metastatic uveal melanoma can spread to the liver. In fact, the liver is the most common organ in the body affected by spread of this type of eye cancer. In 90% to 95% of cases, the melanoma spreads to the liver.

The metastases traveling in the blood may be too small or spread out to be easily seen, so it is important to check early to see if the uveal (ocular) melanoma has spread. On average, liver metastasis happens 27 months after a uveal melanoma diagnosis. There are several different types of tests, and it is important to check with your doctor to see which kind is right for you.

While most metastases tend to be found in the liver, uveal melanoma can also spread to other areas:

• Lungs, in 24% of cases
• Bone, in 16% of case
• Skin, in 11% of cases

 Although it can spread to the lymph nodes or brain, it is not common for this cancer to spread to these areas.

How Does the Eyes’ Immune Response Change How the Disease Progresses?

Certain areas of the body have a special status called immune privilege. This can have both pros and cons when fighting metastatic uveal melanoma.

Here is how immune privilege works. Your body’s immune system works to protect you from infections and diseases. When your immune system detects a health issue, it creates antibodies to fight the problem. Sometimes the fight between the antibodies and the invading disease causes what is known as an inflammatory response, which can cause swelling and a rise in temperature.

If the area of the body, like your eye, has immune privilege, it means that the inflammatory response that usually helps part of the body to heal is limited. One reason for this may be that swelling or higher temperature from the response may damage the delicate eye tissues, so that part of the body protects itself from possible damage.

Knowing about immune privilege of the eye has encouraged researchers to develop certain types of new treatments. For example, stem cells are less likely to be rejected in the eye than in other parts of the body, so there may be some future treatments from that area. 

Some immunotherapy drugs are being used to treat metastatic uveal melanoma. These drugs target the immune system and are supposed to help the system recognize and attack cancer cells. In one type of drug, a bispecific T cell engager – tebentafusp (Kimmtrak) – one part of the drug attaches to immune cells while another part attaches to the melanoma cells. These two together help the immune system attack the cancer cells.

Some immune cells have “checkpoint proteins” that need to be turned off before the immune response can start. Melanoma cells travel to these points to avoid being attacked by the immune system. Some drugs are focused on turning on the immune response in these areas and allowing the body to fight the melanoma.

Immunotherapy drugs are not effective for everyone, but they may be helpful to some people. A lot of important information is being collected from clinical trials that are underway to target metastatic uveal melanoma and boost health and survival.

What Are Other Complications of Metastatic Uveal Melanoma?

Metastasis to other parts of the body is the main complication of uveal melanoma, but it may cause other issues:

• Glaucoma: As the uveal melanoma grows, the increased pressure in the eye can cause glaucoma. Most forms of glaucoma happen when the eye’s drainage system becomes clogged so the fluid in the eye cannot drain. The fluid buildup causes pressure in the eye. Eye pain, redness and blurry vision, and headaches may happen if glaucoma develops. If the pressure in the eye stays too high for too long, it starts to affect the optic nerve. That can lead to permanent vision loss. Noticing the symptoms and getting help early can help protect your vision.
• Retinal detachment: Large uveal melanomas can cause your retina to detach. The retina is the layer of tissue in the back of your eye that is light sensitive. When it is pulled away from the back of your eye, you may see small dark spots or squiggles that float across your vision (floaters), flashes of light, or a dark shadow on the sides or in the middle of your vision. The symptoms of a detached retina can happen quickly. If this condition is not treated, it can cause vision loss or blindness. If caught quickly, it can be treated.
• Other types of vision loss: Depending upon where in the eye the uveal melanoma develops, even small melanomas could cause loss of side or center vision, or total vision loss in extreme cases.

What Is the Outlook for Metastatic Uveal Melanoma?

Statistics for different types of cancer are tracked in the Surveillance, Epidemiology, and End Results (SEER) database, maintained by the National Cancer Institute (NCI). To track cancer spread, the SEER database groups cancers in to three stages:

• Localized: No sign that the cancer has spread outside of the eye.
• Regional: The cancer has spread outside the eye to nearby structures or lymph nodes.
• Distant: The cancer has spread to distant parts of the body, such as the liver.

Survival rates vary, depending on the stages:

• When melanoma does not spread outside the eye, the 5-year relative survival rate is about 85%.
• The 5-year survival rate for those with disease that has spread is 71%.
• If the melanoma has spread to distant parts of the body, the 5-year relative survival rate is 13%.
• The 5-year relative survival rate for people with iris melanoma – a very rare form of eye cancer – is more than 95%.

Metastatic uveal melanoma can be life-threatening, but there are ways to live a longer and healthier life. Ask your doctor to discuss new treatments and help you to find new therapies or clinical trials. Without treatment, after the tumor has metastasized, the average survival time can be a matter of months. But very effective treatments for the cancer are available. Survival rates improve as new treatments continue to be discovered. Along with that, living a healthy lifestyle with a combination of stress management, exercise, and diet changes can create a positive physical and mental environment as your body tries to fight off the disease and heal.