What You Should Know About Uveal Melanoma

Uveal melanoma, commonly referred to as ocular melanoma, arises from neural crest-derived melanocytes of the choroid, iris and the ciliary body. Considered to be an uncommon type of malignant tumor, it can affect any of the three above mentioned areas. Because there are no lymphatic channels to the uveal tract, the risk of metastases is rather high with this type of diagnosis and occurs through local extension and/or blood-borne dissemination. Unfortunately, it can quickly rise to a life-threatening case because the common area afflicted is the liver. [1]

Causes and Symptoms

There is some evidence to suggest that there is a small subset of hereditary factors that may contribute to the rare diagnosis. The other causes are very similar to that in other melanoma cases – with the chief culprit being exposed to UV. Statistics indicate that of the 5-6 million people diagnosed each year in both the United States and Europe, Caucasian and/or Europeans seem to be the most affected population. About 50% of those diagnosed unfortunately develop metastatic disease despite efficient control of the primary tumor. [2]

The most common symptoms reported include:

  • Blurry Vision
  • Growing dark spot on the iris of the eye
  • Loss of field of vision
  • Floaters (spots/squiggles)
  • Flashes of light

Common Treatment Modalities

Traditional treatment options are broken down into five main types and vary depending on the size of the tumor and the results of the biopsy. Sometimes, the oncologists choose to observe the patient. In close observation changes are monitored; even the smallest change in the patient’s condition is tracked. If the tumor isn’t growing or the vision is unaffected an immediate decision to perform a surgical procedure may be delayed until there is an absolute need for surgical intervention.

Surgery is the most common treatment for intraocular melanoma with the following procedures being utilized:

  • Resection: Surgery to remove the tumor and a small amount of healthy tissue around the eye.
  • Enucleation: Surgery to remove the eye and part of the optic nerve. This is done if vision cannot be saved and the tumor is large, has spread to the optic nerve, or causes high pressure inside the eye. After surgery, the patient is usually fitted for an artificial eye resembling his/her original eye.
  • Exenteration: Surgery to remove the eye and eyelid, and muscles, nerves, and fat in the eye socket.
  • Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing.

There are a few different venues of radiation therapies that may be performed:

  • External radiation therapy uses a machine outside the body to send radiation toward cancer. These types of external radiation therapy include:
  • Charged-particle external beam radiation therapy is a type of external-beam radiation therapy. A special radiation therapy machine aims tiny, invisible particles, called protons or helium ions, at the cancer cells to kill them with little damage to nearby normal tissues. Charged-particle radiation therapy uses a different type of radiation than the x-ray type of radiation therapy.
  • Gamma Knife therapy is a type of stereotactic radiosurgery used for some melanomas. It aims tightly focused gamma rays directly at the tumor so there is little damage to healthy tissue. Gamma Knife therapy is not considered surgery and is not used to remove a tumor.
  • Localized plaque radiation therapy is a type of internal radiation therapy that may be used for tumors of the eye. Radioactive seeds are attached to one side of a disk, called a plaque, and placed directly on the outside wall of the eye near the tumor. The side of the plaque with the seeds on it faces the eyeball, aiming radiation at the tumor.

Newer Treatment Options Being Explored Include Adjuvant Therapies

Adjuvant therapies are those used in conjunction or after first points of attacking the cancerous tumors are performed. Of special interest are oncolytic viral therapies. Viral therapies most often used on those diagnosed with uveal melanoma include combining adenovirus therapy in use with other drug options used shown to lyse cancer cells and halt further progression. [3]

[1] Lane AM, Kim IK, Gragoudas ES. Survival Rates in Patients After Treatment for Metastasis From Uveal Melanoma. JAMA Ophthalmol. Published online June 28, 2018. doi:10.1001/jamaophthalmol.2018.2466

[2] Krantz, B. A., Dave, N., Komatsubara, K. M., Marr, B. P., & Carvajal, R. D. (2017). Uveal melanoma: epidemiology, etiology, and treatment of primary disease. Clinical Ophthalmology (Auckland, N.Z.)11, 279–289. http://doi.org/10.2147/OPTH.S89591

[3] Li, X., Yuan, L., Zhao, J., Yang, H., Yang, Y., Zhang, Y., & Cun, B. (2017). Adenovirus-based strategies enhance antitumor capability through p53-mediated downregulation of MGMT in uveal melanoma. Cancer Biology & Therapy18(3), 194–199. http://doi.org/10.1080/15384047.2017.1294287

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