The most common cancer found in the eye is cancer that has spread from elsewhere in the body. However, of the cancers that originate in the eye, ocular melanoma is the most prevalent. Ocular melanoma is thankfully rare, said Mruthyunjaya, but many patients are at risk. Pre-cancerous choroidal nevi are found in five to eight percent of people, and one in 9,000 of these cases will convert to melanoma. Mruthyunjaya has been involved in research to better understand the genetic makeup of ocular melanomas and predict which are more likely to spread from the eye.
Much like its genetic cousin, cutaneous melanoma, ocular melanoma has a high rate of metastasis to other parts of the body. “Fifty percent of our patients ultimately develop metastatic disease, said Mruthyunjaya. “So we have to be very aggressive.” For patients with ocular melanoma, Mruthyunjaya teams up with Sunil Reddy, MD, a clinical oncologist, and Beth Beadle, MD, PhD, a radiation oncologist, to manage the multi-modal treatment for this more complex population.
“Just as physicians who handle cutaneous melanoma deal with a very challenging disease, we see that same scenario play out with ocular melanoma,” said Mruthyunjaya. “It has its own slippery course that we have to try to control.”
Treatment for ocular melanoma often involves a surgical procedure to remove the tumor or prepare it for radiation. With the new team in place, a new form of radiation treatment for ocular melanoma is now available at Stanford. Using sophisticated planning software to more accurately target the tumor, the technique, called ocular brachytherapy, involves temporarily placing a radioactive implant on the eye, which is in place for four to six days. The implant can vary in size and shape based on the location and size of the tumor. This technique delivers a high dose of radiation directly to the tumor with minimal doses to adjacent normal tissues, and is an ideal treatment for patients with small or medium-sized tumors.
“Because the eye is mobile and easily accessible to the outside world, we can use a radioactive implant to treat intra-ocular melanoma, rather than using external radiation therapy,” said Beadle, who joined Stanford in January to lead the head and neck radiation oncology program, after being recruited from MD Anderson. External radiation therapy would take weeks of daily treatment with risk of significant radiation doses to neighboring tissues, and still not provide a curative dose, she said. “Brachytherapy provides a very high dose of curative radiation to the tumor and effectively zero to low doses of radiation to the surrounding eyelashes, eyebrows, brain, nerves and other eye.”
Another option for radiation treatment of ocular melanomas is proton therapy, which has been offered in the Bay Area for several years. This therapy has benefits for larger ocular tumors that are not amenable to the brachytherapy procedure, but for small and medium-sized tumors, the ability to implant radiation therapy is the optimal way of delivering curative dose and minimizing side effects, added Beadle, associate professor of radiation-oncology. “It’s not a one size fits all situation,” she said. Beadle and Mruthyunjaya treated their first patient at Stanford with brachytherapy in April.
“Treating eye cancers is almost always a multidisciplinary effort,” said Goldberg. “Not only have we recruited premier eye doctors and surgeons to manage the cases directly, but we have the best in chemotherapy, radiation and all of the other elements of cancer care that are critical for successful patient outcomes.”
The Ocular Oncology Program also utilizes Stanford’s strength in cancer genetics to help manage patient’s therapies. “We are very aggressive in doing biopsies of these tumors to better understand the ability to predict which patients are more or less likely to develop metastasis,” said Mruthyunjaya. “Our goal is to identify populations of patients that we know are at higher risk for developing these diseases. We work with colleagues in medical oncology to deliver targeted treatments for patients at high risk of developing metastasis, while sparing patients at low risk from the toxicities of some of these therapies.”