It is likely that you have heard of cancer of the skin. What most people don’t know is that there are different types of this disease. The most deadly of all develops in the cells that give color to skin (melanocytes).
Melanocytes are located throughout the skin, including in the uveal tract in eyes. This means that melanoma can also develop in eyes. This type of cancer is known as ocular melanoma. It accounts for most eye cancer related cases.
Treatment options are available for this melanoma. Some are aimed at complete removal of the tumors while others are meant to prolong life expectancy. The hard thing about treating cancer is that it keeps migrating from one location to another. This can be avoided by going for routine eye checkups which may help catch the disease early enough.
What is ocular melanoma?
Cancers are usually named according to the body regions they invade. Below are subtypes of ocular melanoma;
- Uveal melanoma – what is uveal melanoma? It is a type that develops in the uvea. This is a tract located in back of the eye and made up of three layers. Uveal melanoma can begin in the iris, choroid or ciliary body. Melanoma cells in ciliary body have a tendency to spread to liver.
- Conjunctival melanoma – this type develops in the conjunctiva. This is the transparent membrane that protects inner eye surface. It is often characterized by an almost colorless tumor and has a tendency of spreading to lungs. This type is very rare.
- Choroidal melanoma – this is a more common subtype. It develops in the layer of back eye that contains blood vessels (choroid). Since it is located behind the retina, it is not possible to see the tumor when looking in the mirror. This makes choroidal melanoma harder to diagnose early.
Ocular melanoma symptoms
One of the reasons as to why ocular melanoma is dangerous is because it rarely causes any noticeable signs. In fact, tumors are often found during eye tests. When they occur, ocular melanoma symptoms may include;
- Inability to see peripheral objects
- A black spot or patch on the colored part of eye (iris)
- Blurred or compromised vision
- Tendency to see shadows or flashes
It is common for ocular melanoma to spread to liver and sometimes to lungs. When this happens, symptoms such as unexplained weight loss, vomiting, nausea and lump in upper abdomen may occur. See your doctor immediately for medical diagnosis. As it is with any other cancer, even the slightest delay will reduce survival rate as the disease advances.
Ocular melanoma causes
Experts are yet to agree on what exactly causes ocular melanoma. Since it attacks melanocytes, there are reasons to associate it with exposure to UV radiation.
Normally, melanomas develop when mutated cells divide rapidly and fail to die as they should. This leads to accumulation of unwanted cells which develop into a tumor. The following factors may increase the chances of mutation in eye melanocytes;
- UV radiation – being exposed to natural or artificial UV radiation for long can damage melanocytes’ DNA and cause mutation. The outer surface of the eye receives most light and therefore is more likely to be affected.
- Atypical moles – atypical moles are benign. However, people with a condition known as atypical mole syndrome are known to be more affected by melanoma. If you have this condition, you can have up to 100 moles throughout the skin. The risk is even higher if one of the moles is inside eye.
- Hereditary factors – Caucasians are more prone to melanoma. Much the same can be said about individuals with blue or green eyes, red hair or fair skin.
- Age – most melanomas are reported in people older than 50 years of age.
People with dark spots or patches on conjunctiva show a tendency of developing melanoma in these areas. The condition is known as acquired melanosis.
Ocular melanoma prognosis and staging
Ocular melanoma prognosis is best before the disease has spread to the liver or lungs. OM spreads through the blood system unlike other melanomas which first spread through the lymphatic system. It is for this reason that it tends to spread to liver more often. It is estimated than half of all OM tumors will metastasize. Metastasis can also lead to melanoma in lungs especially with conjunctival melanoma.
Once it has spread, OM prognosis is very poor. Life expectancy without treatment is averaged at 5 months after metastasis. Fortunately, effective treatment options and advanced ocular melanoma foundations are available today. More precise mechanisms to identify melanoma cancer stages have also improved overall cancer treatment. Patients are still able to live longer and productive lives even after positive diagnosis.
Melanomas are staged on basis of the much they have spread. In situ melanomas or stage I tumors are fairly easy to treat. Stage II marks tumors which have penetrated into the dermis. In stage III and IV, tumors have spread to other organs or tissues. It is in these later stages that cancer is most deadly.
Small tumors are only likely to lead to complications if they form in critical parts such as near pupil. For example, a tumor on iris may interfere with how the iris controls opening and closing of the pupil. Tumors can in fact push the pupil out of its position.
If not removed, a tumor inside eye will keep exerting pressure. This usually results in pain and interrupted vision. You may also find that the affected eye is always red. Since malignant tumors tend to grow indefinitely, large tumors will ultimately take away vision in one way or another.
The worst complication associated with OM is spreading to other organs. Local tumors in the eye can be removed effectively especially with surgery. The same cannot be said for tumors that have metastasized. The problem is that you may successful treat one tumor only for two more to pop in different organs. How fast does melanoma spread? Well it depends on its location. For example, melanoma on the choroid is likely to spread much faster due to presence of blood vessels in the layer. By the time a melanoma is 2 mm thick, it has penetrated the dermis and will soon find blood vessels. It can take weeks or months and sometimes years for melanomas to metastasize.
Ocular melanoma diagnosis
If you have any reasons to suspect OM, see your doctor immediately. The following tests will be conducted to confirm diagnosis;
Use of eye drops
These are meant to open up the pupil for easier examination. It is not a test itself but an important part of several other tests.
Malignant tumors do develop their own network of blood vessels. Doctors check the outside of eye for signs of blood vessels that normally should not be there. This may indicate the presence of a tumor in the eye. After that, special instruments such as ophthalmoscopy will be used to check for tumors inside eye.
During ultrasound scans, a picture of inside eye will be built on a computer screen using radio waves. A doctor places a device known as a transducer on eyelid while the eye is closed to make the scans.
This test examines the back of eye for presence of tumors. During the test, the doctor will put eye drops before injecting a dye usually in the arm. The dye will be traced with a specialized camera as it reaches the choroid.
Biopsy is a common diagnostic tool for infections and diseases such as cancer. A small piece of tissue is extracted and taken to the lab for observation under a microscope. Although highly effective, eye biopsies for OM diagnosis are not always necessary.
Your doctor may see it fit to check for signs of metastasis. In most cases, a blood test will be done to check the level of liver functions. Other tests include MRIs, CT scans and ultrasounds.
Ocular melanoma treatment
Small eye melanomas can be removed even without risk of vision loss. In fact, some eye melanomas are only closely monitored without treatment. Things get a bit complicated when the tumors have spread or grown big. Such tumors can be removed with the following ocular melanoma treatment options;
This treatment for melanoma uses a very cold substance to kill melanoma tumors. It only works for in situ and small tumors. Its use is not very popular nowadays. After the treatment, patients are sometimes given chemotherapy eye drops.
This method makes use of high powered rays to kill melanoma cells. The rays are directed in such a way that they will not destroy healthy cells. Radiotherapy can be used alone or alongside other treatments such as surgery. It may be given externally or internally.
Side effects may include pain, vision interference and sometimes compromised eyesight. The side effects are usually improved with other treatments afterwards.
Here, lasers are used to destroy melanoma cells. Infrared lasers are commonly used. This treatment is rarely used alone.
Melanoma immunotherapy is not very common when treating OM. The therapy works by boosting the immune system. It is an effective metastatic melanoma treatment especially when surgery is not an option. Immunotherapy however comes with an array of side effects.
Almost all forms of cancers will be removed with surgery in one way or another. In the case of OM, any or combination of the following surgeries may be performed;
- Excisional surgery – this involves removing the tumor itself and a small surrounding tissue. It is very effective for in situ tumors. Sometimes, radiotherapy is used afterwards.
- Enucleation – Large melanomas sometimes make it necessary that the whole eye be removed. An implant will be inserted to during recovery. Afterwards, a custom-made artificial eye will be inserted.
Ocular melanoma is a cancer that starts in melanocytes inside eyes. It hardly produces notable symptoms other than presence of a tumor. Melanomas that start in the choroid are a bit harder to catch during self-examination. It is therefore advised to go for routine eye tests.
People with red hair, blue eyes and light skins tend to be more prone to the disease. There are reasons to believe that exposure to both natural or artificial UV radiation is one of choroidal melanoma causes.
If the cancer is detected early, it is easily treatable. Survival rate is also high for in situ melanomas. About 50% of all ocular melanomas will spread. Their nature to spread through blood vessels puts the liver at a higher risk of being invaded by spreading OM cells.
You may find it helpful to learn more about skin cancer and topics such as anal melanoma, melanoma on vulva and so on. Such are quite dangerous diseases that unfortunately most people rarely find it necessary to learn about.