How effective is plaque radiation therapy for eye melanoma?

The authors assessed the effectiveness of a specific radiation therapy called plaque brachytherapy in treating eye melanoma. 

Radiation therapy (directing a beam of radiation at the tumor site in order to kill cancer cells) is the standard treatment in uveal melanoma. Plaque brachytherapy is the most widely used radiation therapy for uveal melanoma, especially choroidal melanoma. It delivers a high radiation dose to the tumor, reducing radiation exposure to the surrounding healthy tissues. The plaque (radioactive element and the carrier) is surgically placed directly into or very close to the cancer site. It is usually kept there for 4 to 7 days, depending on the size of the tumor and the strength of the radiation.

In larger sized uveal melanomas (stages T3-T4 as defined by the size of the tumor [T]), however, there is a greater risk of developing metastasis (spread of cancer to other parts of the body) when treated with plaque brachytherapy. Therefore, outcomes of this radiation treatment need to be thoroughly evaluated.

The authors aimed to analyze the effectiveness of plaque radiation therapy in eye melanoma patients.

47 uveal melanoma (stage T3/T4) patients were treated with plaque brachytherapy over a 10-year period. The minimum follow-up time was 6 months. The average tumor thickness before the surgery (how far the melanoma reached) was 6.8 mm. The average diameter of the tumor was 15.8 mm. 

At 47 months, cancer growth was stopped at the primary cancer site for 91% of patients. 89% of patients retained their vision after treatment. The common side-effects following radiation therapy were retinal damage (66%), damage to the eye nerves (51%), cataracts (blurring of the eye lens [36%]) and glaucoma (loss of vision [17%]). Overall, 53% maintained 20/200 vision (classified as legally blind in the U.S). 32% of patients developed metastasis. 9% of patients did not experience long-term vision complications following treatment.