A malignant choroidal melanoma (also known in technical language as "malignant uveal melanoma") is by definition a malignant tumor that develops directly in the eye. It arises from the pigmented cells in the choroid. It is referred to as malignant, since it can also form metastases, ie secondary tumors, in other parts of the body or can grow into the surrounding tissue from the eye. Although not all choroidal melanomas are malignant in the same way. However, because malignant choroidal melanomas can be life-threatening, you should make an appointment with the doctor as soon as possible in case of suspected disease.
While retinoblastoma is the most prevalent type of eye cancer or malignancy in children, choroidal melanoma is most common in adults. According to the German Cancer Society, there are five to six new cases per 1,000,000 inhabitants per year, so the incidence of choroidal melanoma is 400 to 500 new cases in Germany. Most of these melanomas of the uvea, ie the middle eye skin, originate from the choroid (choroid), which is located between the leather and the iris of the eye. Another five percent of the choroidal melanomas are in the iris and ten percent in the ciliary body where the lens is suspended. Choroidal melanomas almost always occur only on one side.
According to statistics, such an eye tumor develops on average at 59 years for women and 66 years for men. However, younger people are not sure about such an eye ulcer: In women between the ages of 20 and 30, melanoma is the most common malignant tumor among men and women in the German and Austrian Hematology & Medical Oncology Society, according to the Guideline Adolescents and Young Adults.
According to a report by the Berlin Charité, mortality from choroidal melanoma is on average four to five percent in the first five years. Symptoms and therapy depend on the type of ocular melanoma.
A choroidal melanoma is often discovered only by chance, because it is outwardly not visible and often causes no symptoms for a long time. Only in the advanced stage does a choroidal melanoma appear in a rounded protrusion with an irregular surface. The tumor may or may not be darkly speckled (pigmented). Another characteristic of uveal melanoma is retinal detachment.
In a choroidal melanoma, the pigment cells of the choroid proliferate unchecked. According to the latest scientific findings, the causes of choroidal melanoma are not yet fully understood. It is believed that among other things UV radiation plays a role in the formation. People with ocular melanocytosis (increased presence of pigment cells in the eye) with a genetic predisposition in the form of mutations (GNAQ / GNA11 genes) or with dysplastic Naevi (clinically evident birthmarks / liver spots in the eye) are also considered to be more at risk for this cancer.
A choroidal melanoma can also develop from an already existing choroidal nevus, ie a congenital benign tumor in the interior of the eye.
The risk of contracting a uveal melanoma may increase, among other things, according to the following factors, according to the Society for the Diagnosis and Treatment of Hematological and Oncological Diseases:
Genetic / constitutional factors
- UV radiation
- Veins and dysplastic Naevi
- Familial or genetic predisposition
Acquired / toxic factors
- UV radiation (especially in childhood and adolescence) • melanocytic nevi (benign malformation of pigment cells)
- Childhood cancer with radiation or chemotherapy
When does a metastatic risk exist?
A choroidal melanoma does not necessarily scatter. According to Berliner Charité, however, there are various risk factors that make the formation of metastases more likely. These include, for example, clinical aspects such as the tumor location, size and limitation as well as the histology of the choroidal melanoma, for example, whether vascular loops and certain genetic factors are present.
Since so-called monosomy 3 (that is, chromosome 3 occurs only once instead of twice) in choroidal melanoma is considered particularly meaningful for prognosis, the physician can check the chromosome status and thus the risk group of a patient to make a diagnosis. He takes tissue and examines it.
Often, the ophthalmologist discovers a choroidal melanoma more or less randomly during a (routine) examination. In some cases, sufferers themselves realize that something is wrong, for example, because the vision of the affected eye worsens or the gaze flickers.
If there is a suspicion of choroidal melanoma, the ophthalmologist first examines the inside of the eye with the aid of an ophthalmoscope. Also possible is the diagnosis by means of ultrasound and magnetic resonance imaging (MRI).
The doctor examines the eye using a so-called indirect ophthalmoscope. He wears this ophthalmoscope either on his head, as glasses or he is attached to the slit lamp. A magnifying glass, which the doctor holds in front of the eye, makes the background of the eye and thus typical signs of a tumor visible.
According to the Charité Berlin, ultrasound examination (ultrasound) is an important method for detecting choroidal melanoma. The doctor places a small ultrasound head on the affected eye and directs a sound beam directly at the tumor. The reflection of the beam records the shape of the eye ulcer and its size.
Optical Coherence Tomography (OCT) is painless and non-contact. The ophthalmologist uses a laser to scan the retina and choroid.
In fluorescein angiography, or FAG for short, the doctor injects a dye into a vein of the patient's arm. About 20 seconds later, he reaches the blood vessels in the eye via the bloodstream, where he visualizes the blood flow and distribution of the blood vessels. The doctor makes images for evaluation, with the help of which he can identify typical symptoms of the choroidal melanoma.
How a choroidal melanoma is treated depends on the stage. According to the Berlin Charité, some choroidal melanomas remain virtually unchanged over a long period of time. More often, however, the tumors grow, destroy the retina and make sufferers look worse on the diseased eye.
Malignant choroidal melanomas may in some cases spread to other parts of the body and form daughter tumors there, which may limit organ function and ultimately lead to death. Mainly such metastases occur in the choroidal melanoma in the liver, but also in the lungs and bones. Since the daughter tumors grow very slowly, they are often not found at the time of diagnosis and treatment and can still occur years after successful therapy.
Choroidal melanomas are divided into stages from 1 to 4. In localized melanoma stages 1 to 3 is operated according to the German Cancer Society usually. The chances of recovery in this case depend on whether the tumor can be completely removed. If the disease has reached stage 4, a cure is also possible in patients with single metastases, but survival is reduced in the majority of cases. Often the doctor can only do palliative work and only alleviate the symptoms. Immunotherapy is effective and usually extends life expectancy.
A choroidal melanoma initially causes no clear symptoms. Only in the advanced stage it comes to different complaints, above all visual restrictions. Affected then often see flickering, flashes, double or blurry, the vision becomes worse or the visual field darkens (scotoma). Headache may also indicate choroidal melanoma.
If the choroidal melanoma is scattering on other organs, it may also cause symptoms there. Pulmonary, skin or liver metastases include symptoms of paralysis, impaired performance or pressure pain, among the common symptoms.
If the doctor has a choroidal melanoma, you should start the therapy as soon as possible. The longer the tumor remains untreated, the more damage it will do to the eye, and the risk of metastases also increasing.
What treatment the doctor uses depends on where the choroidal melanoma is located and how big it is. For example, an operation that removes the entire eye or just the tumor, but also a radiation therapy (brachytherapy), in which 90 percent of the cases, the eye is preserved.
Removal of the eye
In so-called enucleation, the doctor surgically removes the entire eye. Such a radical procedure may be necessary if the tumor has already reached a certain size. During surgery, the patient is under general anesthesia. Instead of the natural eye, the surgeon uses an implant that is sutured with eye muscles and conjunctiva and is (almost) not recognizable from the outside as a "wrong eye". Normally, patients can leave the hospital after two to three days. After a healing period of four to eight weeks, a specialist then uses an artificial eye made of glass as a prosthesis, which moves the remaining eye muscles to a certain degree. A well-adapted glass prosthesis is visually indistinguishable from a natural eye. Serious complications from the procedure are rare.
Note: Although the doctor removes the tumor in the eye during this procedure, it can not be ruled out that metastases will nevertheless form. Since the vision of an eye is lost, the visual performance (eg, spatial vision) of the patient is correspondingly limited.
Surgical removal of the tumor
In certain cases it may be sufficient to remove only the tumor itself. According to the experts of the Berlin Charité, such an intervention in a choroidal melanoma is very likely to completely destroy the tumor. But there is no guarantee for this as well as for the preservation of the eyesight. Even with this form of therapy, secondary tumors can grow despite successful intervention if they have already formed before the start of therapy.
Irradiation has become the most widely used form of therapy for choroidal melanoma. Your goal is to destroy the tumor, but to preserve the eye. The quality of vision depends on the location and size of the melanoma. Either the doctor sews a small beam carrier on the diseased eye (brachytherapy) or it is irradiated with positively charged hydrogen atom cores (proton therapy). While brachytherapy is only possible if the tumor does not exceed a size of six millimeters, proton therapy can also achieve larger tumors deep inside the body. As with the other two forms of treatment, metastases may form despite irradiation, but this need not be the case.
Therapy for metastases
Unfortunately, according to the German Cancer Society, around 30 percent of cases involve distant metastases associated with choroidal melanoma. This means that in other organs, especially in the liver, daughter tumors form. Even years after the therapy of the eye is completed, this can still happen. In such cases, the doctor often chooses a local therapy that specifically targets the affected organ. Such treatments include transarterial chemoembolization (TACE), in which the physician selectively treats the metastases with chemotherapy (eg, Fotemustin for choroidal melanoma metastases in the liver) and then closes the metastasis-supplying vessel, or the selective internal chemoembolization Radiotherapy (SIRT), in which tiny radioactive beads are introduced into the diseased areas of the liver via catheters.
An operative intervention is also conceivable. If the doctor succeeds in surgically removing all metastases, the further prognosis is good. According to the German Cancer Society, immunotherapy and other drug therapies are usually ineffective in the case of choroidal melanoma.
There is currently no standardized recommendation for follow-up after choroidal melanoma therapy. However, regular check-up by the ophthalmologist, which should be visited approximately every six months, makes sense. In addition, it is advisable to have the liver checked every three to six months by the family doctor in order to detect metastases that may develop with delay.