If you are newly diagnosed with a primary choroidal “intraocular” melanoma, you are likely to have no signs or symptoms of metastatic melanoma. According to a recent study utilizing total body PET/CT to stage uveal melanoma patients at diagnosis, 1% of (T1 and T2) sized tumors and 4% of (T3 and T4) size tumors were found to have their melanomas spread to other parts of their body at the time diagnosis of their eye tumor. But, up to 50% will subsequently be found to have metastasis over the following years. Be assured that many patients diagnosed and treated for choroidal melanoma will not develop metastatic melanoma.
Tumor size is the most well-verified predictor of a patient’s risk for metastatic melanoma. It makes sense that treatments that limit the tumor’s ability to enlarge will decrease the chance of metastasis. This is why most eye cancer specialists believe destroying or removing an eye cancer offers the best method to prevent future spread from that tumor.
Treatment is not thought to affect micrometastasis (too small to find) already present at the time of the eye treatment. This is why patients need periodic general medical examinations (surveys) after treatment for their intraocular melanoma.
Eighty-five percent of metastatic choroidal melanoma will be initially found in the liver. Metastases can be discovered by blood tests (liver function studies) when a patient has no symptoms. Other patients may notice abdominal fullness, discomfort and a loss of appetite. Though the liver may be the first place tumors are found, it is likely that other organs are affected. Your doctor should look for other tumor sites (e.g. subcutaneous nodules, lung, bone and brain metastasis). If a liver or skin metastasis is suspected a biopsy can be used to aspirate tumor cells for cytopathologic examination.
Since most patients start with liver tumors, therapy typically depends on the presence or absence of metastases outside of the liver, the number (size and location) of tumors within the liver, and how they affect liver function.
Treatment Options
The liver is (initially) the exclusive site of choroidal melanoma metastasis in about 40% of patients. Of those patients, most have diffuse or multi-focal tumors which cannot be removed. Treatment options depend on the size, location and rate of tumor growth.
Local Surgery: If a patient has a slow growing solitary metastasis, surgical excision may be an option. There have been no evidence-based studies that prove whether this type of surgery prolongs survival or improves the quality of life of patients. All patients who undergo surgery for a solitary liver, lung or brain metastasis have to recover from a major surgery.
Systemic Chemotherapy: When tumors are found in different parts of the body, then treatment is directed at the whole body. In these cases, your doctor may offer injection of standard intravenous chemotherapy. Unfortunately, standard chemotherapy drugs usually do not cure metastatic choroidal melanoma. There are clinical trials of new chemotherapy drugs which may be more effective.
Chemo-embolization: This treatment involves injecting a combination of chemotherapy and particles into the arteries that feed the metastatic tumors within the liver. For example, cisplatin chemotherapy and polyvinyl sponge particles are injected intra-arterially to the liver. Side effects have typically included fever, right upper quadrant abdominal pain, elevation of liver enzymes and paralysis of the intestine lasting 1 to 2 days after the procedure. It is important to understand that this is a local treatment aimed at shrinking the liver metastasis and prolonging life. It is not considered curative.
Biologic Therapy: Biologic therapy treats cancer by helping the immune system function better. The immune system is your body’s natural defense. It is a network of organs and cells distributed throughout your body. It not only defends against bacteria and viruses but also helps find and destroy cancer cells. Recent investigations focused on metastatic cutaneous melanoma have been very promising.
Observation
It is a patient’s right to choose or refuse treatment. Since many of the previously mentioned treatments can decrease a patient’s quality of life, each decision to treat must be weighed against potential side effects. You should always discuss the risk of possible side-effects and the potential benefits with your medical oncologist prior to treatment.
